1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
4 * All Rights Reserved.
5 */
6 #include "xfs.h"
7 #include "xfs_fs.h"
8 #include "xfs_shared.h"
9 #include "xfs_format.h"
10 #include "xfs_log_format.h"
11 #include "xfs_trans_resv.h"
12 #include "xfs_bit.h"
13 #include "xfs_sb.h"
14 #include "xfs_mount.h"
15 #include "xfs_defer.h"
16 #include "xfs_inode.h"
17 #include "xfs_trans.h"
18 #include "xfs_log.h"
19 #include "xfs_log_priv.h"
20 #include "xfs_log_recover.h"
21 #include "xfs_trans_priv.h"
22 #include "xfs_alloc.h"
23 #include "xfs_ialloc.h"
24 #include "xfs_trace.h"
25 #include "xfs_icache.h"
26 #include "xfs_error.h"
27 #include "xfs_buf_item.h"
28 #include "xfs_ag.h"
29 #include "xfs_quota.h"
30 #include "xfs_reflink.h"
31
32 #define BLK_AVG(blk1, blk2) ((blk1+blk2) >> 1)
33
34 STATIC int
35 xlog_find_zeroed(
36 struct xlog *,
37 xfs_daddr_t *);
38 STATIC int
39 xlog_clear_stale_blocks(
40 struct xlog *,
41 xfs_lsn_t);
42 STATIC int
43 xlog_do_recovery_pass(
44 struct xlog *, xfs_daddr_t, xfs_daddr_t, int, xfs_daddr_t *);
45
46 /*
47 * Sector aligned buffer routines for buffer create/read/write/access
48 */
49
50 /*
51 * Verify the log-relative block number and length in basic blocks are valid for
52 * an operation involving the given XFS log buffer. Returns true if the fields
53 * are valid, false otherwise.
54 */
55 static inline bool
56 xlog_verify_bno(
57 struct xlog *log,
58 xfs_daddr_t blk_no,
59 int bbcount)
60 {
61 if (blk_no < 0 || blk_no >= log->l_logBBsize)
62 return false;
63 if (bbcount <= 0 || (blk_no + bbcount) > log->l_logBBsize)
64 return false;
65 return true;
66 }
67
68 /*
69 * Allocate a buffer to hold log data. The buffer needs to be able to map to
70 * a range of nbblks basic blocks at any valid offset within the log.
71 */
72 static char *
73 xlog_alloc_buffer(
74 struct xlog *log,
75 int nbblks)
76 {
77 /*
78 * Pass log block 0 since we don't have an addr yet, buffer will be
79 * verified on read.
80 */
81 if (XFS_IS_CORRUPT(log->l_mp, !xlog_verify_bno(log, 0, nbblks))) {
82 xfs_warn(log->l_mp, "Invalid block length (0x%x) for buffer",
83 nbblks);
84 return NULL;
85 }
86
87 /*
88 * We do log I/O in units of log sectors (a power-of-2 multiple of the
89 * basic block size), so we round up the requested size to accommodate
90 * the basic blocks required for complete log sectors.
91 *
92 * In addition, the buffer may be used for a non-sector-aligned block
93 * offset, in which case an I/O of the requested size could extend
94 * beyond the end of the buffer. If the requested size is only 1 basic
95 * block it will never straddle a sector boundary, so this won't be an
96 * issue. Nor will this be a problem if the log I/O is done in basic
97 * blocks (sector size 1). But otherwise we extend the buffer by one
98 * extra log sector to ensure there's space to accommodate this
99 * possibility.
100 */
101 if (nbblks > 1 && log->l_sectBBsize > 1)
102 nbblks += log->l_sectBBsize;
103 nbblks = round_up(nbblks, log->l_sectBBsize);
104 return kvzalloc(BBTOB(nbblks), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
105 }
106
107 /*
108 * Return the address of the start of the given block number's data
109 * in a log buffer. The buffer covers a log sector-aligned region.
110 */
111 static inline unsigned int
112 xlog_align(
113 struct xlog *log,
114 xfs_daddr_t blk_no)
115 {
116 return BBTOB(blk_no & ((xfs_daddr_t)log->l_sectBBsize - 1));
117 }
118
119 static int
120 xlog_do_io(
121 struct xlog *log,
122 xfs_daddr_t blk_no,
123 unsigned int nbblks,
124 char *data,
125 enum req_op op)
126 {
127 int error;
128
129 if (XFS_IS_CORRUPT(log->l_mp, !xlog_verify_bno(log, blk_no, nbblks))) {
130 xfs_warn(log->l_mp,
131 "Invalid log block/length (0x%llx, 0x%x) for buffer",
132 blk_no, nbblks);
133 return -EFSCORRUPTED;
134 }
135
136 blk_no = round_down(blk_no, log->l_sectBBsize);
137 nbblks = round_up(nbblks, log->l_sectBBsize);
138 ASSERT(nbblks > 0);
139
140 error = xfs_rw_bdev(log->l_targ->bt_bdev, log->l_logBBstart + blk_no,
141 BBTOB(nbblks), data, op);
142 if (error && !xlog_is_shutdown(log)) {
143 xfs_alert(log->l_mp,
144 "log recovery %s I/O error at daddr 0x%llx len %d error %d",
145 op == REQ_OP_WRITE ? "write" : "read",
146 blk_no, nbblks, error);
147 }
148 return error;
149 }
150
151 STATIC int
152 xlog_bread_noalign(
153 struct xlog *log,
154 xfs_daddr_t blk_no,
155 int nbblks,
156 char *data)
157 {
158 return xlog_do_io(log, blk_no, nbblks, data, REQ_OP_READ);
159 }
160
161 STATIC int
162 xlog_bread(
163 struct xlog *log,
164 xfs_daddr_t blk_no,
165 int nbblks,
166 char *data,
167 char **offset)
168 {
169 int error;
170
171 error = xlog_do_io(log, blk_no, nbblks, data, REQ_OP_READ);
172 if (!error)
173 *offset = data + xlog_align(log, blk_no);
174 return error;
175 }
176
177 STATIC int
178 xlog_bwrite(
179 struct xlog *log,
180 xfs_daddr_t blk_no,
181 int nbblks,
182 char *data)
183 {
184 return xlog_do_io(log, blk_no, nbblks, data, REQ_OP_WRITE);
185 }
186
187 #ifdef DEBUG
188 /*
189 * dump debug superblock and log record information
190 */
191 STATIC void
192 xlog_header_check_dump(
193 xfs_mount_t *mp,
194 xlog_rec_header_t *head)
195 {
196 xfs_debug(mp, "%s: SB : uuid = %pU, fmt = %d",
197 __func__, &mp->m_sb.sb_uuid, XLOG_FMT);
198 xfs_debug(mp, " log : uuid = %pU, fmt = %d",
199 &head->h_fs_uuid, be32_to_cpu(head->h_fmt));
200 }
201 #else
202 #define xlog_header_check_dump(mp, head)
203 #endif
204
205 /*
206 * check log record header for recovery
207 */
208 STATIC int
209 xlog_header_check_recover(
210 xfs_mount_t *mp,
211 xlog_rec_header_t *head)
212 {
213 ASSERT(head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM));
214
215 /*
216 * IRIX doesn't write the h_fmt field and leaves it zeroed
217 * (XLOG_FMT_UNKNOWN). This stops us from trying to recover
218 * a dirty log created in IRIX.
219 */
220 if (XFS_IS_CORRUPT(mp, head->h_fmt != cpu_to_be32(XLOG_FMT))) {
221 xfs_warn(mp,
222 "dirty log written in incompatible format - can't recover");
223 xlog_header_check_dump(mp, head);
224 return -EFSCORRUPTED;
225 }
226 if (XFS_IS_CORRUPT(mp, !uuid_equal(&mp->m_sb.sb_uuid,
227 &head->h_fs_uuid))) {
228 xfs_warn(mp,
229 "dirty log entry has mismatched uuid - can't recover");
230 xlog_header_check_dump(mp, head);
231 return -EFSCORRUPTED;
232 }
233 return 0;
234 }
235
236 /*
237 * read the head block of the log and check the header
238 */
239 STATIC int
240 xlog_header_check_mount(
241 xfs_mount_t *mp,
242 xlog_rec_header_t *head)
243 {
244 ASSERT(head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM));
245
246 if (uuid_is_null(&head->h_fs_uuid)) {
247 /*
248 * IRIX doesn't write the h_fs_uuid or h_fmt fields. If
249 * h_fs_uuid is null, we assume this log was last mounted
250 * by IRIX and continue.
251 */
252 xfs_warn(mp, "null uuid in log - IRIX style log");
253 } else if (XFS_IS_CORRUPT(mp, !uuid_equal(&mp->m_sb.sb_uuid,
254 &head->h_fs_uuid))) {
255 xfs_warn(mp, "log has mismatched uuid - can't recover");
256 xlog_header_check_dump(mp, head);
257 return -EFSCORRUPTED;
258 }
259 return 0;
260 }
261
262 /*
263 * This routine finds (to an approximation) the first block in the physical
264 * log which contains the given cycle. It uses a binary search algorithm.
265 * Note that the algorithm can not be perfect because the disk will not
266 * necessarily be perfect.
267 */
268 STATIC int
269 xlog_find_cycle_start(
270 struct xlog *log,
271 char *buffer,
272 xfs_daddr_t first_blk,
273 xfs_daddr_t *last_blk,
274 uint cycle)
275 {
276 char *offset;
277 xfs_daddr_t mid_blk;
278 xfs_daddr_t end_blk;
279 uint mid_cycle;
280 int error;
281
282 end_blk = *last_blk;
283 mid_blk = BLK_AVG(first_blk, end_blk);
284 while (mid_blk != first_blk && mid_blk != end_blk) {
285 error = xlog_bread(log, mid_blk, 1, buffer, &offset);
286 if (error)
287 return error;
288 mid_cycle = xlog_get_cycle(offset);
289 if (mid_cycle == cycle)
290 end_blk = mid_blk; /* last_half_cycle == mid_cycle */
291 else
292 first_blk = mid_blk; /* first_half_cycle == mid_cycle */
293 mid_blk = BLK_AVG(first_blk, end_blk);
294 }
295 ASSERT((mid_blk == first_blk && mid_blk+1 == end_blk) ||
296 (mid_blk == end_blk && mid_blk-1 == first_blk));
297
298 *last_blk = end_blk;
299
300 return 0;
301 }
302
303 /*
304 * Check that a range of blocks does not contain stop_on_cycle_no.
305 * Fill in *new_blk with the block offset where such a block is
306 * found, or with -1 (an invalid block number) if there is no such
307 * block in the range. The scan needs to occur from front to back
308 * and the pointer into the region must be updated since a later
309 * routine will need to perform another test.
310 */
311 STATIC int
312 xlog_find_verify_cycle(
313 struct xlog *log,
314 xfs_daddr_t start_blk,
315 int nbblks,
316 uint stop_on_cycle_no,
317 xfs_daddr_t *new_blk)
318 {
319 xfs_daddr_t i, j;
320 uint cycle;
321 char *buffer;
322 xfs_daddr_t bufblks;
323 char *buf = NULL;
324 int error = 0;
325
326 /*
327 * Greedily allocate a buffer big enough to handle the full
328 * range of basic blocks we'll be examining. If that fails,
329 * try a smaller size. We need to be able to read at least
330 * a log sector, or we're out of luck.
331 */
332 bufblks = roundup_pow_of_two(nbblks);
333 while (bufblks > log->l_logBBsize)
334 bufblks >>= 1;
335 while (!(buffer = xlog_alloc_buffer(log, bufblks))) {
336 bufblks >>= 1;
337 if (bufblks < log->l_sectBBsize)
338 return -ENOMEM;
339 }
340
341 for (i = start_blk; i < start_blk + nbblks; i += bufblks) {
342 int bcount;
343
344 bcount = min(bufblks, (start_blk + nbblks - i));
345
346 error = xlog_bread(log, i, bcount, buffer, &buf);
347 if (error)
348 goto out;
349
350 for (j = 0; j < bcount; j++) {
351 cycle = xlog_get_cycle(buf);
352 if (cycle == stop_on_cycle_no) {
353 *new_blk = i+j;
354 goto out;
355 }
356
357 buf += BBSIZE;
358 }
359 }
360
361 *new_blk = -1;
362
363 out:
364 kvfree(buffer);
365 return error;
366 }
367
368 static inline int
369 xlog_logrec_hblks(struct xlog *log, struct xlog_rec_header *rh)
370 {
371 if (xfs_has_logv2(log->l_mp)) {
372 int h_size = be32_to_cpu(rh->h_size);
373
374 if ((be32_to_cpu(rh->h_version) & XLOG_VERSION_2) &&
375 h_size > XLOG_HEADER_CYCLE_SIZE)
376 return DIV_ROUND_UP(h_size, XLOG_HEADER_CYCLE_SIZE);
377 }
378 return 1;
379 }
380
381 /*
382 * Potentially backup over partial log record write.
383 *
384 * In the typical case, last_blk is the number of the block directly after
385 * a good log record. Therefore, we subtract one to get the block number
386 * of the last block in the given buffer. extra_bblks contains the number
387 * of blocks we would have read on a previous read. This happens when the
388 * last log record is split over the end of the physical log.
389 *
390 * extra_bblks is the number of blocks potentially verified on a previous
391 * call to this routine.
392 */
393 STATIC int
394 xlog_find_verify_log_record(
395 struct xlog *log,
396 xfs_daddr_t start_blk,
397 xfs_daddr_t *last_blk,
398 int extra_bblks)
399 {
400 xfs_daddr_t i;
401 char *buffer;
402 char *offset = NULL;
403 xlog_rec_header_t *head = NULL;
404 int error = 0;
405 int smallmem = 0;
406 int num_blks = *last_blk - start_blk;
407 int xhdrs;
408
409 ASSERT(start_blk != 0 || *last_blk != start_blk);
410
411 buffer = xlog_alloc_buffer(log, num_blks);
412 if (!buffer) {
413 buffer = xlog_alloc_buffer(log, 1);
414 if (!buffer)
415 return -ENOMEM;
416 smallmem = 1;
417 } else {
418 error = xlog_bread(log, start_blk, num_blks, buffer, &offset);
419 if (error)
420 goto out;
421 offset += ((num_blks - 1) << BBSHIFT);
422 }
423
424 for (i = (*last_blk) - 1; i >= 0; i--) {
425 if (i < start_blk) {
426 /* valid log record not found */
427 xfs_warn(log->l_mp,
428 "Log inconsistent (didn't find previous header)");
429 ASSERT(0);
430 error = -EFSCORRUPTED;
431 goto out;
432 }
433
434 if (smallmem) {
435 error = xlog_bread(log, i, 1, buffer, &offset);
436 if (error)
437 goto out;
438 }
439
440 head = (xlog_rec_header_t *)offset;
441
442 if (head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
443 break;
444
445 if (!smallmem)
446 offset -= BBSIZE;
447 }
448
449 /*
450 * We hit the beginning of the physical log & still no header. Return
451 * to caller. If caller can handle a return of -1, then this routine
452 * will be called again for the end of the physical log.
453 */
454 if (i == -1) {
455 error = 1;
456 goto out;
457 }
458
459 /*
460 * We have the final block of the good log (the first block
461 * of the log record _before_ the head. So we check the uuid.
462 */
463 if ((error = xlog_header_check_mount(log->l_mp, head)))
464 goto out;
465
466 /*
467 * We may have found a log record header before we expected one.
468 * last_blk will be the 1st block # with a given cycle #. We may end
469 * up reading an entire log record. In this case, we don't want to
470 * reset last_blk. Only when last_blk points in the middle of a log
471 * record do we update last_blk.
472 */
473 xhdrs = xlog_logrec_hblks(log, head);
474
475 if (*last_blk - i + extra_bblks !=
476 BTOBB(be32_to_cpu(head->h_len)) + xhdrs)
477 *last_blk = i;
478
479 out:
480 kvfree(buffer);
481 return error;
482 }
483
484 /*
485 * Head is defined to be the point of the log where the next log write
486 * could go. This means that incomplete LR writes at the end are
487 * eliminated when calculating the head. We aren't guaranteed that previous
488 * LR have complete transactions. We only know that a cycle number of
489 * current cycle number -1 won't be present in the log if we start writing
490 * from our current block number.
491 *
492 * last_blk contains the block number of the first block with a given
493 * cycle number.
494 *
495 * Return: zero if normal, non-zero if error.
496 */
497 STATIC int
498 xlog_find_head(
499 struct xlog *log,
500 xfs_daddr_t *return_head_blk)
501 {
502 char *buffer;
503 char *offset;
504 xfs_daddr_t new_blk, first_blk, start_blk, last_blk, head_blk;
505 int num_scan_bblks;
506 uint first_half_cycle, last_half_cycle;
507 uint stop_on_cycle;
508 int error, log_bbnum = log->l_logBBsize;
509
510 /* Is the end of the log device zeroed? */
511 error = xlog_find_zeroed(log, &first_blk);
512 if (error < 0) {
513 xfs_warn(log->l_mp, "empty log check failed");
514 return error;
515 }
516 if (error == 1) {
517 *return_head_blk = first_blk;
518
519 /* Is the whole lot zeroed? */
520 if (!first_blk) {
521 /* Linux XFS shouldn't generate totally zeroed logs -
522 * mkfs etc write a dummy unmount record to a fresh
523 * log so we can store the uuid in there
524 */
525 xfs_warn(log->l_mp, "totally zeroed log");
526 }
527
528 return 0;
529 }
530
531 first_blk = 0; /* get cycle # of 1st block */
532 buffer = xlog_alloc_buffer(log, 1);
533 if (!buffer)
534 return -ENOMEM;
535
536 error = xlog_bread(log, 0, 1, buffer, &offset);
537 if (error)
538 goto out_free_buffer;
539
540 first_half_cycle = xlog_get_cycle(offset);
541
542 last_blk = head_blk = log_bbnum - 1; /* get cycle # of last block */
543 error = xlog_bread(log, last_blk, 1, buffer, &offset);
544 if (error)
545 goto out_free_buffer;
546
547 last_half_cycle = xlog_get_cycle(offset);
548 ASSERT(last_half_cycle != 0);
549
550 /*
551 * If the 1st half cycle number is equal to the last half cycle number,
552 * then the entire log is stamped with the same cycle number. In this
553 * case, head_blk can't be set to zero (which makes sense). The below
554 * math doesn't work out properly with head_blk equal to zero. Instead,
555 * we set it to log_bbnum which is an invalid block number, but this
556 * value makes the math correct. If head_blk doesn't changed through
557 * all the tests below, *head_blk is set to zero at the very end rather
558 * than log_bbnum. In a sense, log_bbnum and zero are the same block
559 * in a circular file.
560 */
561 if (first_half_cycle == last_half_cycle) {
562 /*
563 * In this case we believe that the entire log should have
564 * cycle number last_half_cycle. We need to scan backwards
565 * from the end verifying that there are no holes still
566 * containing last_half_cycle - 1. If we find such a hole,
567 * then the start of that hole will be the new head. The
568 * simple case looks like
569 * x | x ... | x - 1 | x
570 * Another case that fits this picture would be
571 * x | x + 1 | x ... | x
572 * In this case the head really is somewhere at the end of the
573 * log, as one of the latest writes at the beginning was
574 * incomplete.
575 * One more case is
576 * x | x + 1 | x ... | x - 1 | x
577 * This is really the combination of the above two cases, and
578 * the head has to end up at the start of the x-1 hole at the
579 * end of the log.
580 *
581 * In the 256k log case, we will read from the beginning to the
582 * end of the log and search for cycle numbers equal to x-1.
583 * We don't worry about the x+1 blocks that we encounter,
584 * because we know that they cannot be the head since the log
585 * started with x.
586 */
587 head_blk = log_bbnum;
588 stop_on_cycle = last_half_cycle - 1;
589 } else {
590 /*
591 * In this case we want to find the first block with cycle
592 * number matching last_half_cycle. We expect the log to be
593 * some variation on
594 * x + 1 ... | x ... | x
595 * The first block with cycle number x (last_half_cycle) will
596 * be where the new head belongs. First we do a binary search
597 * for the first occurrence of last_half_cycle. The binary
598 * search may not be totally accurate, so then we scan back
599 * from there looking for occurrences of last_half_cycle before
600 * us. If that backwards scan wraps around the beginning of
601 * the log, then we look for occurrences of last_half_cycle - 1
602 * at the end of the log. The cases we're looking for look
603 * like
604 * v binary search stopped here
605 * x + 1 ... | x | x + 1 | x ... | x
606 * ^ but we want to locate this spot
607 * or
608 * <---------> less than scan distance
609 * x + 1 ... | x ... | x - 1 | x
610 * ^ we want to locate this spot
611 */
612 stop_on_cycle = last_half_cycle;
613 error = xlog_find_cycle_start(log, buffer, first_blk, &head_blk,
614 last_half_cycle);
615 if (error)
616 goto out_free_buffer;
617 }
618
619 /*
620 * Now validate the answer. Scan back some number of maximum possible
621 * blocks and make sure each one has the expected cycle number. The
622 * maximum is determined by the total possible amount of buffering
623 * in the in-core log. The following number can be made tighter if
624 * we actually look at the block size of the filesystem.
625 */
626 num_scan_bblks = min_t(int, log_bbnum, XLOG_TOTAL_REC_SHIFT(log));
627 if (head_blk >= num_scan_bblks) {
628 /*
629 * We are guaranteed that the entire check can be performed
630 * in one buffer.
631 */
632 start_blk = head_blk - num_scan_bblks;
633 if ((error = xlog_find_verify_cycle(log,
634 start_blk, num_scan_bblks,
635 stop_on_cycle, &new_blk)))
636 goto out_free_buffer;
637 if (new_blk != -1)
638 head_blk = new_blk;
639 } else { /* need to read 2 parts of log */
640 /*
641 * We are going to scan backwards in the log in two parts.
642 * First we scan the physical end of the log. In this part
643 * of the log, we are looking for blocks with cycle number
644 * last_half_cycle - 1.
645 * If we find one, then we know that the log starts there, as
646 * we've found a hole that didn't get written in going around
647 * the end of the physical log. The simple case for this is
648 * x + 1 ... | x ... | x - 1 | x
649 * <---------> less than scan distance
650 * If all of the blocks at the end of the log have cycle number
651 * last_half_cycle, then we check the blocks at the start of
652 * the log looking for occurrences of last_half_cycle. If we
653 * find one, then our current estimate for the location of the
654 * first occurrence of last_half_cycle is wrong and we move
655 * back to the hole we've found. This case looks like
656 * x + 1 ... | x | x + 1 | x ...
657 * ^ binary search stopped here
658 * Another case we need to handle that only occurs in 256k
659 * logs is
660 * x + 1 ... | x ... | x+1 | x ...
661 * ^ binary search stops here
662 * In a 256k log, the scan at the end of the log will see the
663 * x + 1 blocks. We need to skip past those since that is
664 * certainly not the head of the log. By searching for
665 * last_half_cycle-1 we accomplish that.
666 */
667 ASSERT(head_blk <= INT_MAX &&
668 (xfs_daddr_t) num_scan_bblks >= head_blk);
669 start_blk = log_bbnum - (num_scan_bblks - head_blk);
670 if ((error = xlog_find_verify_cycle(log, start_blk,
671 num_scan_bblks - (int)head_blk,
672 (stop_on_cycle - 1), &new_blk)))
673 goto out_free_buffer;
674 if (new_blk != -1) {
675 head_blk = new_blk;
676 goto validate_head;
677 }
678
679 /*
680 * Scan beginning of log now. The last part of the physical
681 * log is good. This scan needs to verify that it doesn't find
682 * the last_half_cycle.
683 */
684 start_blk = 0;
685 ASSERT(head_blk <= INT_MAX);
686 if ((error = xlog_find_verify_cycle(log,
687 start_blk, (int)head_blk,
688 stop_on_cycle, &new_blk)))
689 goto out_free_buffer;
690 if (new_blk != -1)
691 head_blk = new_blk;
692 }
693
694 validate_head:
695 /*
696 * Now we need to make sure head_blk is not pointing to a block in
697 * the middle of a log record.
698 */
699 num_scan_bblks = XLOG_REC_SHIFT(log);
700 if (head_blk >= num_scan_bblks) {
701 start_blk = head_blk - num_scan_bblks; /* don't read head_blk */
702
703 /* start ptr at last block ptr before head_blk */
704 error = xlog_find_verify_log_record(log, start_blk, &head_blk, 0);
705 if (error == 1)
706 error = -EIO;
707 if (error)
708 goto out_free_buffer;
709 } else {
710 start_blk = 0;
711 ASSERT(head_blk <= INT_MAX);
712 error = xlog_find_verify_log_record(log, start_blk, &head_blk, 0);
713 if (error < 0)
714 goto out_free_buffer;
715 if (error == 1) {
716 /* We hit the beginning of the log during our search */
717 start_blk = log_bbnum - (num_scan_bblks - head_blk);
718 new_blk = log_bbnum;
719 ASSERT(start_blk <= INT_MAX &&
720 (xfs_daddr_t) log_bbnum-start_blk >= 0);
721 ASSERT(head_blk <= INT_MAX);
722 error = xlog_find_verify_log_record(log, start_blk,
723 &new_blk, (int)head_blk);
724 if (error == 1)
725 error = -EIO;
726 if (error)
727 goto out_free_buffer;
728 if (new_blk != log_bbnum)
729 head_blk = new_blk;
730 } else if (error)
731 goto out_free_buffer;
732 }
733
734 kvfree(buffer);
735 if (head_blk == log_bbnum)
736 *return_head_blk = 0;
737 else
738 *return_head_blk = head_blk;
739 /*
740 * When returning here, we have a good block number. Bad block
741 * means that during a previous crash, we didn't have a clean break
742 * from cycle number N to cycle number N-1. In this case, we need
743 * to find the first block with cycle number N-1.
744 */
745 return 0;
746
747 out_free_buffer:
748 kvfree(buffer);
749 if (error)
750 xfs_warn(log->l_mp, "failed to find log head");
751 return error;
752 }
753
754 /*
755 * Seek backwards in the log for log record headers.
756 *
757 * Given a starting log block, walk backwards until we find the provided number
758 * of records or hit the provided tail block. The return value is the number of
759 * records encountered or a negative error code. The log block and buffer
760 * pointer of the last record seen are returned in rblk and rhead respectively.
761 */
762 STATIC int
763 xlog_rseek_logrec_hdr(
764 struct xlog *log,
765 xfs_daddr_t head_blk,
766 xfs_daddr_t tail_blk,
767 int count,
768 char *buffer,
769 xfs_daddr_t *rblk,
770 struct xlog_rec_header **rhead,
771 bool *wrapped)
772 {
773 int i;
774 int error;
775 int found = 0;
776 char *offset = NULL;
777 xfs_daddr_t end_blk;
778
779 *wrapped = false;
780
781 /*
782 * Walk backwards from the head block until we hit the tail or the first
783 * block in the log.
784 */
785 end_blk = head_blk > tail_blk ? tail_blk : 0;
786 for (i = (int) head_blk - 1; i >= end_blk; i--) {
787 error = xlog_bread(log, i, 1, buffer, &offset);
788 if (error)
789 goto out_error;
790
791 if (*(__be32 *) offset == cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
792 *rblk = i;
793 *rhead = (struct xlog_rec_header *) offset;
794 if (++found == count)
795 break;
796 }
797 }
798
799 /*
800 * If we haven't hit the tail block or the log record header count,
801 * start looking again from the end of the physical log. Note that
802 * callers can pass head == tail if the tail is not yet known.
803 */
804 if (tail_blk >= head_blk && found != count) {
805 for (i = log->l_logBBsize - 1; i >= (int) tail_blk; i--) {
806 error = xlog_bread(log, i, 1, buffer, &offset);
807 if (error)
808 goto out_error;
809
810 if (*(__be32 *)offset ==
811 cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
812 *wrapped = true;
813 *rblk = i;
814 *rhead = (struct xlog_rec_header *) offset;
815 if (++found == count)
816 break;
817 }
818 }
819 }
820
821 return found;
822
823 out_error:
824 return error;
825 }
826
827 /*
828 * Seek forward in the log for log record headers.
829 *
830 * Given head and tail blocks, walk forward from the tail block until we find
831 * the provided number of records or hit the head block. The return value is the
832 * number of records encountered or a negative error code. The log block and
833 * buffer pointer of the last record seen are returned in rblk and rhead
834 * respectively.
835 */
836 STATIC int
837 xlog_seek_logrec_hdr(
838 struct xlog *log,
839 xfs_daddr_t head_blk,
840 xfs_daddr_t tail_blk,
841 int count,
842 char *buffer,
843 xfs_daddr_t *rblk,
844 struct xlog_rec_header **rhead,
845 bool *wrapped)
846 {
847 int i;
848 int error;
849 int found = 0;
850 char *offset = NULL;
851 xfs_daddr_t end_blk;
852
853 *wrapped = false;
854
855 /*
856 * Walk forward from the tail block until we hit the head or the last
857 * block in the log.
858 */
859 end_blk = head_blk > tail_blk ? head_blk : log->l_logBBsize - 1;
860 for (i = (int) tail_blk; i <= end_blk; i++) {
861 error = xlog_bread(log, i, 1, buffer, &offset);
862 if (error)
863 goto out_error;
864
865 if (*(__be32 *) offset == cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
866 *rblk = i;
867 *rhead = (struct xlog_rec_header *) offset;
868 if (++found == count)
869 break;
870 }
871 }
872
873 /*
874 * If we haven't hit the head block or the log record header count,
875 * start looking again from the start of the physical log.
876 */
877 if (tail_blk > head_blk && found != count) {
878 for (i = 0; i < (int) head_blk; i++) {
879 error = xlog_bread(log, i, 1, buffer, &offset);
880 if (error)
881 goto out_error;
882
883 if (*(__be32 *)offset ==
884 cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
885 *wrapped = true;
886 *rblk = i;
887 *rhead = (struct xlog_rec_header *) offset;
888 if (++found == count)
889 break;
890 }
891 }
892 }
893
894 return found;
895
896 out_error:
897 return error;
898 }
899
900 /*
901 * Calculate distance from head to tail (i.e., unused space in the log).
902 */
903 static inline int
904 xlog_tail_distance(
905 struct xlog *log,
906 xfs_daddr_t head_blk,
907 xfs_daddr_t tail_blk)
908 {
909 if (head_blk < tail_blk)
910 return tail_blk - head_blk;
911
912 return tail_blk + (log->l_logBBsize - head_blk);
913 }
914
915 /*
916 * Verify the log tail. This is particularly important when torn or incomplete
917 * writes have been detected near the front of the log and the head has been
918 * walked back accordingly.
919 *
920 * We also have to handle the case where the tail was pinned and the head
921 * blocked behind the tail right before a crash. If the tail had been pushed
922 * immediately prior to the crash and the subsequent checkpoint was only
923 * partially written, it's possible it overwrote the last referenced tail in the
924 * log with garbage. This is not a coherency problem because the tail must have
925 * been pushed before it can be overwritten, but appears as log corruption to
926 * recovery because we have no way to know the tail was updated if the
927 * subsequent checkpoint didn't write successfully.
928 *
929 * Therefore, CRC check the log from tail to head. If a failure occurs and the
930 * offending record is within max iclog bufs from the head, walk the tail
931 * forward and retry until a valid tail is found or corruption is detected out
932 * of the range of a possible overwrite.
933 */
934 STATIC int
935 xlog_verify_tail(
936 struct xlog *log,
937 xfs_daddr_t head_blk,
938 xfs_daddr_t *tail_blk,
939 int hsize)
940 {
941 struct xlog_rec_header *thead;
942 char *buffer;
943 xfs_daddr_t first_bad;
944 int error = 0;
945 bool wrapped;
946 xfs_daddr_t tmp_tail;
947 xfs_daddr_t orig_tail = *tail_blk;
948
949 buffer = xlog_alloc_buffer(log, 1);
950 if (!buffer)
951 return -ENOMEM;
952
953 /*
954 * Make sure the tail points to a record (returns positive count on
955 * success).
956 */
957 error = xlog_seek_logrec_hdr(log, head_blk, *tail_blk, 1, buffer,
958 &tmp_tail, &thead, &wrapped);
959 if (error < 0)
960 goto out;
961 if (*tail_blk != tmp_tail)
962 *tail_blk = tmp_tail;
963
964 /*
965 * Run a CRC check from the tail to the head. We can't just check
966 * MAX_ICLOGS records past the tail because the tail may point to stale
967 * blocks cleared during the search for the head/tail. These blocks are
968 * overwritten with zero-length records and thus record count is not a
969 * reliable indicator of the iclog state before a crash.
970 */
971 first_bad = 0;
972 error = xlog_do_recovery_pass(log, head_blk, *tail_blk,
973 XLOG_RECOVER_CRCPASS, &first_bad);
974 while ((error == -EFSBADCRC || error == -EFSCORRUPTED) && first_bad) {
975 int tail_distance;
976
977 /*
978 * Is corruption within range of the head? If so, retry from
979 * the next record. Otherwise return an error.
980 */
981 tail_distance = xlog_tail_distance(log, head_blk, first_bad);
982 if (tail_distance > BTOBB(XLOG_MAX_ICLOGS * hsize))
983 break;
984
985 /* skip to the next record; returns positive count on success */
986 error = xlog_seek_logrec_hdr(log, head_blk, first_bad, 2,
987 buffer, &tmp_tail, &thead, &wrapped);
988 if (error < 0)
989 goto out;
990
991 *tail_blk = tmp_tail;
992 first_bad = 0;
993 error = xlog_do_recovery_pass(log, head_blk, *tail_blk,
994 XLOG_RECOVER_CRCPASS, &first_bad);
995 }
996
997 if (!error && *tail_blk != orig_tail)
998 xfs_warn(log->l_mp,
999 "Tail block (0x%llx) overwrite detected. Updated to 0x%llx",
1000 orig_tail, *tail_blk);
1001 out:
1002 kvfree(buffer);
1003 return error;
1004 }
1005
1006 /*
1007 * Detect and trim torn writes from the head of the log.
1008 *
1009 * Storage without sector atomicity guarantees can result in torn writes in the
1010 * log in the event of a crash. Our only means to detect this scenario is via
1011 * CRC verification. While we can't always be certain that CRC verification
1012 * failure is due to a torn write vs. an unrelated corruption, we do know that
1013 * only a certain number (XLOG_MAX_ICLOGS) of log records can be written out at
1014 * one time. Therefore, CRC verify up to XLOG_MAX_ICLOGS records at the head of
1015 * the log and treat failures in this range as torn writes as a matter of
1016 * policy. In the event of CRC failure, the head is walked back to the last good
1017 * record in the log and the tail is updated from that record and verified.
1018 */
1019 STATIC int
1020 xlog_verify_head(
1021 struct xlog *log,
1022 xfs_daddr_t *head_blk, /* in/out: unverified head */
1023 xfs_daddr_t *tail_blk, /* out: tail block */
1024 char *buffer,
1025 xfs_daddr_t *rhead_blk, /* start blk of last record */
1026 struct xlog_rec_header **rhead, /* ptr to last record */
1027 bool *wrapped) /* last rec. wraps phys. log */
1028 {
1029 struct xlog_rec_header *tmp_rhead;
1030 char *tmp_buffer;
1031 xfs_daddr_t first_bad;
1032 xfs_daddr_t tmp_rhead_blk;
1033 int found;
1034 int error;
1035 bool tmp_wrapped;
1036
1037 /*
1038 * Check the head of the log for torn writes. Search backwards from the
1039 * head until we hit the tail or the maximum number of log record I/Os
1040 * that could have been in flight at one time. Use a temporary buffer so
1041 * we don't trash the rhead/buffer pointers from the caller.
1042 */
1043 tmp_buffer = xlog_alloc_buffer(log, 1);
1044 if (!tmp_buffer)
1045 return -ENOMEM;
1046 error = xlog_rseek_logrec_hdr(log, *head_blk, *tail_blk,
1047 XLOG_MAX_ICLOGS, tmp_buffer,
1048 &tmp_rhead_blk, &tmp_rhead, &tmp_wrapped);
1049 kvfree(tmp_buffer);
1050 if (error < 0)
1051 return error;
1052
1053 /*
1054 * Now run a CRC verification pass over the records starting at the
1055 * block found above to the current head. If a CRC failure occurs, the
1056 * log block of the first bad record is saved in first_bad.
1057 */
1058 error = xlog_do_recovery_pass(log, *head_blk, tmp_rhead_blk,
1059 XLOG_RECOVER_CRCPASS, &first_bad);
1060 if ((error == -EFSBADCRC || error == -EFSCORRUPTED) && first_bad) {
1061 /*
1062 * We've hit a potential torn write. Reset the error and warn
1063 * about it.
1064 */
1065 error = 0;
1066 xfs_warn(log->l_mp,
1067 "Torn write (CRC failure) detected at log block 0x%llx. Truncating head block from 0x%llx.",
1068 first_bad, *head_blk);
1069
1070 /*
1071 * Get the header block and buffer pointer for the last good
1072 * record before the bad record.
1073 *
1074 * Note that xlog_find_tail() clears the blocks at the new head
1075 * (i.e., the records with invalid CRC) if the cycle number
1076 * matches the current cycle.
1077 */
1078 found = xlog_rseek_logrec_hdr(log, first_bad, *tail_blk, 1,
1079 buffer, rhead_blk, rhead, wrapped);
1080 if (found < 0)
1081 return found;
1082 if (found == 0) /* XXX: right thing to do here? */
1083 return -EIO;
1084
1085 /*
1086 * Reset the head block to the starting block of the first bad
1087 * log record and set the tail block based on the last good
1088 * record.
1089 *
1090 * Bail out if the updated head/tail match as this indicates
1091 * possible corruption outside of the acceptable
1092 * (XLOG_MAX_ICLOGS) range. This is a job for xfs_repair...
1093 */
1094 *head_blk = first_bad;
1095 *tail_blk = BLOCK_LSN(be64_to_cpu((*rhead)->h_tail_lsn));
1096 if (*head_blk == *tail_blk) {
1097 ASSERT(0);
1098 return 0;
1099 }
1100 }
1101 if (error)
1102 return error;
1103
1104 return xlog_verify_tail(log, *head_blk, tail_blk,
1105 be32_to_cpu((*rhead)->h_size));
1106 }
1107
1108 /*
1109 * We need to make sure we handle log wrapping properly, so we can't use the
1110 * calculated logbno directly. Make sure it wraps to the correct bno inside the
1111 * log.
1112 *
1113 * The log is limited to 32 bit sizes, so we use the appropriate modulus
1114 * operation here and cast it back to a 64 bit daddr on return.
1115 */
1116 static inline xfs_daddr_t
1117 xlog_wrap_logbno(
1118 struct xlog *log,
1119 xfs_daddr_t bno)
1120 {
1121 int mod;
1122
1123 div_s64_rem(bno, log->l_logBBsize, &mod);
1124 return mod;
1125 }
1126
1127 /*
1128 * Check whether the head of the log points to an unmount record. In other
1129 * words, determine whether the log is clean. If so, update the in-core state
1130 * appropriately.
1131 */
1132 static int
1133 xlog_check_unmount_rec(
1134 struct xlog *log,
1135 xfs_daddr_t *head_blk,
1136 xfs_daddr_t *tail_blk,
1137 struct xlog_rec_header *rhead,
1138 xfs_daddr_t rhead_blk,
1139 char *buffer,
1140 bool *clean)
1141 {
1142 struct xlog_op_header *op_head;
1143 xfs_daddr_t umount_data_blk;
1144 xfs_daddr_t after_umount_blk;
1145 int hblks;
1146 int error;
1147 char *offset;
1148
1149 *clean = false;
1150
1151 /*
1152 * Look for unmount record. If we find it, then we know there was a
1153 * clean unmount. Since 'i' could be the last block in the physical
1154 * log, we convert to a log block before comparing to the head_blk.
1155 *
1156 * Save the current tail lsn to use to pass to xlog_clear_stale_blocks()
1157 * below. We won't want to clear the unmount record if there is one, so
1158 * we pass the lsn of the unmount record rather than the block after it.
1159 */
1160 hblks = xlog_logrec_hblks(log, rhead);
1161 after_umount_blk = xlog_wrap_logbno(log,
1162 rhead_blk + hblks + BTOBB(be32_to_cpu(rhead->h_len)));
1163
1164 if (*head_blk == after_umount_blk &&
1165 be32_to_cpu(rhead->h_num_logops) == 1) {
1166 umount_data_blk = xlog_wrap_logbno(log, rhead_blk + hblks);
1167 error = xlog_bread(log, umount_data_blk, 1, buffer, &offset);
1168 if (error)
1169 return error;
1170
1171 op_head = (struct xlog_op_header *)offset;
1172 if (op_head->oh_flags & XLOG_UNMOUNT_TRANS) {
1173 /*
1174 * Set tail and last sync so that newly written log
1175 * records will point recovery to after the current
1176 * unmount record.
1177 */
1178 xlog_assign_atomic_lsn(&log->l_tail_lsn,
1179 log->l_curr_cycle, after_umount_blk);
1180 log->l_ailp->ail_head_lsn =
1181 atomic64_read(&log->l_tail_lsn);
1182 *tail_blk = after_umount_blk;
1183
1184 *clean = true;
1185 }
1186 }
1187
1188 return 0;
1189 }
1190
1191 static void
1192 xlog_set_state(
1193 struct xlog *log,
1194 xfs_daddr_t head_blk,
1195 struct xlog_rec_header *rhead,
1196 xfs_daddr_t rhead_blk,
1197 bool bump_cycle)
1198 {
1199 /*
1200 * Reset log values according to the state of the log when we
1201 * crashed. In the case where head_blk == 0, we bump curr_cycle
1202 * one because the next write starts a new cycle rather than
1203 * continuing the cycle of the last good log record. At this
1204 * point we have guaranteed that all partial log records have been
1205 * accounted for. Therefore, we know that the last good log record
1206 * written was complete and ended exactly on the end boundary
1207 * of the physical log.
1208 */
1209 log->l_prev_block = rhead_blk;
1210 log->l_curr_block = (int)head_blk;
1211 log->l_curr_cycle = be32_to_cpu(rhead->h_cycle);
1212 if (bump_cycle)
1213 log->l_curr_cycle++;
1214 atomic64_set(&log->l_tail_lsn, be64_to_cpu(rhead->h_tail_lsn));
1215 log->l_ailp->ail_head_lsn = be64_to_cpu(rhead->h_lsn);
1216 }
1217
1218 /*
1219 * Find the sync block number or the tail of the log.
1220 *
1221 * This will be the block number of the last record to have its
1222 * associated buffers synced to disk. Every log record header has
1223 * a sync lsn embedded in it. LSNs hold block numbers, so it is easy
1224 * to get a sync block number. The only concern is to figure out which
1225 * log record header to believe.
1226 *
1227 * The following algorithm uses the log record header with the largest
1228 * lsn. The entire log record does not need to be valid. We only care
1229 * that the header is valid.
1230 *
1231 * We could speed up search by using current head_blk buffer, but it is not
1232 * available.
1233 */
1234 STATIC int
1235 xlog_find_tail(
1236 struct xlog *log,
1237 xfs_daddr_t *head_blk,
1238 xfs_daddr_t *tail_blk)
1239 {
1240 xlog_rec_header_t *rhead;
1241 char *offset = NULL;
1242 char *buffer;
1243 int error;
1244 xfs_daddr_t rhead_blk;
1245 xfs_lsn_t tail_lsn;
1246 bool wrapped = false;
1247 bool clean = false;
1248
1249 /*
1250 * Find previous log record
1251 */
1252 if ((error = xlog_find_head(log, head_blk)))
1253 return error;
1254 ASSERT(*head_blk < INT_MAX);
1255
1256 buffer = xlog_alloc_buffer(log, 1);
1257 if (!buffer)
1258 return -ENOMEM;
1259 if (*head_blk == 0) { /* special case */
1260 error = xlog_bread(log, 0, 1, buffer, &offset);
1261 if (error)
1262 goto done;
1263
1264 if (xlog_get_cycle(offset) == 0) {
1265 *tail_blk = 0;
1266 /* leave all other log inited values alone */
1267 goto done;
1268 }
1269 }
1270
1271 /*
1272 * Search backwards through the log looking for the log record header
1273 * block. This wraps all the way back around to the head so something is
1274 * seriously wrong if we can't find it.
1275 */
1276 error = xlog_rseek_logrec_hdr(log, *head_blk, *head_blk, 1, buffer,
1277 &rhead_blk, &rhead, &wrapped);
1278 if (error < 0)
1279 goto done;
1280 if (!error) {
1281 xfs_warn(log->l_mp, "%s: couldn't find sync record", __func__);
1282 error = -EFSCORRUPTED;
1283 goto done;
1284 }
1285 *tail_blk = BLOCK_LSN(be64_to_cpu(rhead->h_tail_lsn));
1286
1287 /*
1288 * Set the log state based on the current head record.
1289 */
1290 xlog_set_state(log, *head_blk, rhead, rhead_blk, wrapped);
1291 tail_lsn = atomic64_read(&log->l_tail_lsn);
1292
1293 /*
1294 * Look for an unmount record at the head of the log. This sets the log
1295 * state to determine whether recovery is necessary.
1296 */
1297 error = xlog_check_unmount_rec(log, head_blk, tail_blk, rhead,
1298 rhead_blk, buffer, &clean);
1299 if (error)
1300 goto done;
1301
1302 /*
1303 * Verify the log head if the log is not clean (e.g., we have anything
1304 * but an unmount record at the head). This uses CRC verification to
1305 * detect and trim torn writes. If discovered, CRC failures are
1306 * considered torn writes and the log head is trimmed accordingly.
1307 *
1308 * Note that we can only run CRC verification when the log is dirty
1309 * because there's no guarantee that the log data behind an unmount
1310 * record is compatible with the current architecture.
1311 */
1312 if (!clean) {
1313 xfs_daddr_t orig_head = *head_blk;
1314
1315 error = xlog_verify_head(log, head_blk, tail_blk, buffer,
1316 &rhead_blk, &rhead, &wrapped);
1317 if (error)
1318 goto done;
1319
1320 /* update in-core state again if the head changed */
1321 if (*head_blk != orig_head) {
1322 xlog_set_state(log, *head_blk, rhead, rhead_blk,
1323 wrapped);
1324 tail_lsn = atomic64_read(&log->l_tail_lsn);
1325 error = xlog_check_unmount_rec(log, head_blk, tail_blk,
1326 rhead, rhead_blk, buffer,
1327 &clean);
1328 if (error)
1329 goto done;
1330 }
1331 }
1332
1333 /*
1334 * Note that the unmount was clean. If the unmount was not clean, we
1335 * need to know this to rebuild the superblock counters from the perag
1336 * headers if we have a filesystem using non-persistent counters.
1337 */
1338 if (clean)
1339 set_bit(XFS_OPSTATE_CLEAN, &log->l_mp->m_opstate);
1340
1341 /*
1342 * Make sure that there are no blocks in front of the head
1343 * with the same cycle number as the head. This can happen
1344 * because we allow multiple outstanding log writes concurrently,
1345 * and the later writes might make it out before earlier ones.
1346 *
1347 * We use the lsn from before modifying it so that we'll never
1348 * overwrite the unmount record after a clean unmount.
1349 *
1350 * Do this only if we are going to recover the filesystem
1351 *
1352 * NOTE: This used to say "if (!readonly)"
1353 * However on Linux, we can & do recover a read-only filesystem.
1354 * We only skip recovery if NORECOVERY is specified on mount,
1355 * in which case we would not be here.
1356 *
1357 * But... if the -device- itself is readonly, just skip this.
1358 * We can't recover this device anyway, so it won't matter.
1359 */
1360 if (!xfs_readonly_buftarg(log->l_targ))
1361 error = xlog_clear_stale_blocks(log, tail_lsn);
1362
1363 done:
1364 kvfree(buffer);
1365
1366 if (error)
1367 xfs_warn(log->l_mp, "failed to locate log tail");
1368 return error;
1369 }
1370
1371 /*
1372 * Is the log zeroed at all?
1373 *
1374 * The last binary search should be changed to perform an X block read
1375 * once X becomes small enough. You can then search linearly through
1376 * the X blocks. This will cut down on the number of reads we need to do.
1377 *
1378 * If the log is partially zeroed, this routine will pass back the blkno
1379 * of the first block with cycle number 0. It won't have a complete LR
1380 * preceding it.
1381 *
1382 * Return:
1383 * 0 => the log is completely written to
1384 * 1 => use *blk_no as the first block of the log
1385 * <0 => error has occurred
1386 */
1387 STATIC int
1388 xlog_find_zeroed(
1389 struct xlog *log,
1390 xfs_daddr_t *blk_no)
1391 {
1392 char *buffer;
1393 char *offset;
1394 uint first_cycle, last_cycle;
1395 xfs_daddr_t new_blk, last_blk, start_blk;
1396 xfs_daddr_t num_scan_bblks;
1397 int error, log_bbnum = log->l_logBBsize;
1398 int ret = 1;
1399
1400 *blk_no = 0;
1401
1402 /* check totally zeroed log */
1403 buffer = xlog_alloc_buffer(log, 1);
1404 if (!buffer)
1405 return -ENOMEM;
1406 error = xlog_bread(log, 0, 1, buffer, &offset);
1407 if (error)
1408 goto out_free_buffer;
1409
1410 first_cycle = xlog_get_cycle(offset);
1411 if (first_cycle == 0) { /* completely zeroed log */
1412 *blk_no = 0;
1413 goto out_free_buffer;
1414 }
1415
1416 /* check partially zeroed log */
1417 error = xlog_bread(log, log_bbnum-1, 1, buffer, &offset);
1418 if (error)
1419 goto out_free_buffer;
1420
1421 last_cycle = xlog_get_cycle(offset);
1422 if (last_cycle != 0) { /* log completely written to */
1423 ret = 0;
1424 goto out_free_buffer;
1425 }
1426
1427 /* we have a partially zeroed log */
1428 last_blk = log_bbnum-1;
1429 error = xlog_find_cycle_start(log, buffer, 0, &last_blk, 0);
1430 if (error)
1431 goto out_free_buffer;
1432
1433 /*
1434 * Validate the answer. Because there is no way to guarantee that
1435 * the entire log is made up of log records which are the same size,
1436 * we scan over the defined maximum blocks. At this point, the maximum
1437 * is not chosen to mean anything special. XXXmiken
1438 */
1439 num_scan_bblks = XLOG_TOTAL_REC_SHIFT(log);
1440 ASSERT(num_scan_bblks <= INT_MAX);
1441
1442 if (last_blk < num_scan_bblks)
1443 num_scan_bblks = last_blk;
1444 start_blk = last_blk - num_scan_bblks;
1445
1446 /*
1447 * We search for any instances of cycle number 0 that occur before
1448 * our current estimate of the head. What we're trying to detect is
1449 * 1 ... | 0 | 1 | 0...
1450 * ^ binary search ends here
1451 */
1452 if ((error = xlog_find_verify_cycle(log, start_blk,
1453 (int)num_scan_bblks, 0, &new_blk)))
1454 goto out_free_buffer;
1455 if (new_blk != -1)
1456 last_blk = new_blk;
1457
1458 /*
1459 * Potentially backup over partial log record write. We don't need
1460 * to search the end of the log because we know it is zero.
1461 */
1462 error = xlog_find_verify_log_record(log, start_blk, &last_blk, 0);
1463 if (error == 1)
1464 error = -EIO;
1465 if (error)
1466 goto out_free_buffer;
1467
1468 *blk_no = last_blk;
1469 out_free_buffer:
1470 kvfree(buffer);
1471 if (error)
1472 return error;
1473 return ret;
1474 }
1475
1476 /*
1477 * These are simple subroutines used by xlog_clear_stale_blocks() below
1478 * to initialize a buffer full of empty log record headers and write
1479 * them into the log.
1480 */
1481 STATIC void
1482 xlog_add_record(
1483 struct xlog *log,
1484 char *buf,
1485 int cycle,
1486 int block,
1487 int tail_cycle,
1488 int tail_block)
1489 {
1490 xlog_rec_header_t *recp = (xlog_rec_header_t *)buf;
1491
1492 memset(buf, 0, BBSIZE);
1493 recp->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
1494 recp->h_cycle = cpu_to_be32(cycle);
1495 recp->h_version = cpu_to_be32(
1496 xfs_has_logv2(log->l_mp) ? 2 : 1);
1497 recp->h_lsn = cpu_to_be64(xlog_assign_lsn(cycle, block));
1498 recp->h_tail_lsn = cpu_to_be64(xlog_assign_lsn(tail_cycle, tail_block));
1499 recp->h_fmt = cpu_to_be32(XLOG_FMT);
1500 memcpy(&recp->h_fs_uuid, &log->l_mp->m_sb.sb_uuid, sizeof(uuid_t));
1501 }
1502
1503 STATIC int
1504 xlog_write_log_records(
1505 struct xlog *log,
1506 int cycle,
1507 int start_block,
1508 int blocks,
1509 int tail_cycle,
1510 int tail_block)
1511 {
1512 char *offset;
1513 char *buffer;
1514 int balign, ealign;
1515 int sectbb = log->l_sectBBsize;
1516 int end_block = start_block + blocks;
1517 int bufblks;
1518 int error = 0;
1519 int i, j = 0;
1520
1521 /*
1522 * Greedily allocate a buffer big enough to handle the full
1523 * range of basic blocks to be written. If that fails, try
1524 * a smaller size. We need to be able to write at least a
1525 * log sector, or we're out of luck.
1526 */
1527 bufblks = roundup_pow_of_two(blocks);
1528 while (bufblks > log->l_logBBsize)
1529 bufblks >>= 1;
1530 while (!(buffer = xlog_alloc_buffer(log, bufblks))) {
1531 bufblks >>= 1;
1532 if (bufblks < sectbb)
1533 return -ENOMEM;
1534 }
1535
1536 /* We may need to do a read at the start to fill in part of
1537 * the buffer in the starting sector not covered by the first
1538 * write below.
1539 */
1540 balign = round_down(start_block, sectbb);
1541 if (balign != start_block) {
1542 error = xlog_bread_noalign(log, start_block, 1, buffer);
1543 if (error)
1544 goto out_free_buffer;
1545
1546 j = start_block - balign;
1547 }
1548
1549 for (i = start_block; i < end_block; i += bufblks) {
1550 int bcount, endcount;
1551
1552 bcount = min(bufblks, end_block - start_block);
1553 endcount = bcount - j;
1554
1555 /* We may need to do a read at the end to fill in part of
1556 * the buffer in the final sector not covered by the write.
1557 * If this is the same sector as the above read, skip it.
1558 */
1559 ealign = round_down(end_block, sectbb);
1560 if (j == 0 && (start_block + endcount > ealign)) {
1561 error = xlog_bread_noalign(log, ealign, sectbb,
1562 buffer + BBTOB(ealign - start_block));
1563 if (error)
1564 break;
1565
1566 }
1567
1568 offset = buffer + xlog_align(log, start_block);
1569 for (; j < endcount; j++) {
1570 xlog_add_record(log, offset, cycle, i+j,
1571 tail_cycle, tail_block);
1572 offset += BBSIZE;
1573 }
1574 error = xlog_bwrite(log, start_block, endcount, buffer);
1575 if (error)
1576 break;
1577 start_block += endcount;
1578 j = 0;
1579 }
1580
1581 out_free_buffer:
1582 kvfree(buffer);
1583 return error;
1584 }
1585
1586 /*
1587 * This routine is called to blow away any incomplete log writes out
1588 * in front of the log head. We do this so that we won't become confused
1589 * if we come up, write only a little bit more, and then crash again.
1590 * If we leave the partial log records out there, this situation could
1591 * cause us to think those partial writes are valid blocks since they
1592 * have the current cycle number. We get rid of them by overwriting them
1593 * with empty log records with the old cycle number rather than the
1594 * current one.
1595 *
1596 * The tail lsn is passed in rather than taken from
1597 * the log so that we will not write over the unmount record after a
1598 * clean unmount in a 512 block log. Doing so would leave the log without
1599 * any valid log records in it until a new one was written. If we crashed
1600 * during that time we would not be able to recover.
1601 */
1602 STATIC int
1603 xlog_clear_stale_blocks(
1604 struct xlog *log,
1605 xfs_lsn_t tail_lsn)
1606 {
1607 int tail_cycle, head_cycle;
1608 int tail_block, head_block;
1609 int tail_distance, max_distance;
1610 int distance;
1611 int error;
1612
1613 tail_cycle = CYCLE_LSN(tail_lsn);
1614 tail_block = BLOCK_LSN(tail_lsn);
1615 head_cycle = log->l_curr_cycle;
1616 head_block = log->l_curr_block;
1617
1618 /*
1619 * Figure out the distance between the new head of the log
1620 * and the tail. We want to write over any blocks beyond the
1621 * head that we may have written just before the crash, but
1622 * we don't want to overwrite the tail of the log.
1623 */
1624 if (head_cycle == tail_cycle) {
1625 /*
1626 * The tail is behind the head in the physical log,
1627 * so the distance from the head to the tail is the
1628 * distance from the head to the end of the log plus
1629 * the distance from the beginning of the log to the
1630 * tail.
1631 */
1632 if (XFS_IS_CORRUPT(log->l_mp,
1633 head_block < tail_block ||
1634 head_block >= log->l_logBBsize))
1635 return -EFSCORRUPTED;
1636 tail_distance = tail_block + (log->l_logBBsize - head_block);
1637 } else {
1638 /*
1639 * The head is behind the tail in the physical log,
1640 * so the distance from the head to the tail is just
1641 * the tail block minus the head block.
1642 */
1643 if (XFS_IS_CORRUPT(log->l_mp,
1644 head_block >= tail_block ||
1645 head_cycle != tail_cycle + 1))
1646 return -EFSCORRUPTED;
1647 tail_distance = tail_block - head_block;
1648 }
1649
1650 /*
1651 * If the head is right up against the tail, we can't clear
1652 * anything.
1653 */
1654 if (tail_distance <= 0) {
1655 ASSERT(tail_distance == 0);
1656 return 0;
1657 }
1658
1659 max_distance = XLOG_TOTAL_REC_SHIFT(log);
1660 /*
1661 * Take the smaller of the maximum amount of outstanding I/O
1662 * we could have and the distance to the tail to clear out.
1663 * We take the smaller so that we don't overwrite the tail and
1664 * we don't waste all day writing from the head to the tail
1665 * for no reason.
1666 */
1667 max_distance = min(max_distance, tail_distance);
1668
1669 if ((head_block + max_distance) <= log->l_logBBsize) {
1670 /*
1671 * We can stomp all the blocks we need to without
1672 * wrapping around the end of the log. Just do it
1673 * in a single write. Use the cycle number of the
1674 * current cycle minus one so that the log will look like:
1675 * n ... | n - 1 ...
1676 */
1677 error = xlog_write_log_records(log, (head_cycle - 1),
1678 head_block, max_distance, tail_cycle,
1679 tail_block);
1680 if (error)
1681 return error;
1682 } else {
1683 /*
1684 * We need to wrap around the end of the physical log in
1685 * order to clear all the blocks. Do it in two separate
1686 * I/Os. The first write should be from the head to the
1687 * end of the physical log, and it should use the current
1688 * cycle number minus one just like above.
1689 */
1690 distance = log->l_logBBsize - head_block;
1691 error = xlog_write_log_records(log, (head_cycle - 1),
1692 head_block, distance, tail_cycle,
1693 tail_block);
1694
1695 if (error)
1696 return error;
1697
1698 /*
1699 * Now write the blocks at the start of the physical log.
1700 * This writes the remainder of the blocks we want to clear.
1701 * It uses the current cycle number since we're now on the
1702 * same cycle as the head so that we get:
1703 * n ... n ... | n - 1 ...
1704 * ^^^^^ blocks we're writing
1705 */
1706 distance = max_distance - (log->l_logBBsize - head_block);
1707 error = xlog_write_log_records(log, head_cycle, 0, distance,
1708 tail_cycle, tail_block);
1709 if (error)
1710 return error;
1711 }
1712
1713 return 0;
1714 }
1715
1716 /*
1717 * Release the recovered intent item in the AIL that matches the given intent
1718 * type and intent id.
1719 */
1720 void
1721 xlog_recover_release_intent(
1722 struct xlog *log,
1723 unsigned short intent_type,
1724 uint64_t intent_id)
1725 {
1726 struct xfs_defer_pending *dfp, *n;
1727
1728 list_for_each_entry_safe(dfp, n, &log->r_dfops, dfp_list) {
1729 struct xfs_log_item *lip = dfp->dfp_intent;
1730
1731 if (lip->li_type != intent_type)
1732 continue;
1733 if (!lip->li_ops->iop_match(lip, intent_id))
1734 continue;
1735
1736 ASSERT(xlog_item_is_intent(lip));
1737
1738 xfs_defer_cancel_recovery(log->l_mp, dfp);
1739 }
1740 }
1741
1742 int
1743 xlog_recover_iget(
1744 struct xfs_mount *mp,
1745 xfs_ino_t ino,
1746 struct xfs_inode **ipp)
1747 {
1748 int error;
1749
1750 error = xfs_iget(mp, NULL, ino, 0, 0, ipp);
1751 if (error)
1752 return error;
1753
1754 error = xfs_qm_dqattach(*ipp);
1755 if (error) {
1756 xfs_irele(*ipp);
1757 return error;
1758 }
1759
1760 if (VFS_I(*ipp)->i_nlink == 0)
1761 xfs_iflags_set(*ipp, XFS_IRECOVERY);
1762
1763 return 0;
1764 }
1765
1766 /*
1767 * Get an inode so that we can recover a log operation.
1768 *
1769 * Log intent items that target inodes effectively contain a file handle.
1770 * Check that the generation number matches the intent item like we do for
1771 * other file handles. Log intent items defined after this validation weakness
1772 * was identified must use this function.
1773 */
1774 int
1775 xlog_recover_iget_handle(
1776 struct xfs_mount *mp,
1777 xfs_ino_t ino,
1778 uint32_t gen,
1779 struct xfs_inode **ipp)
1780 {
1781 struct xfs_inode *ip;
1782 int error;
1783
1784 error = xlog_recover_iget(mp, ino, &ip);
1785 if (error)
1786 return error;
1787
1788 if (VFS_I(ip)->i_generation != gen) {
1789 xfs_irele(ip);
1790 return -EFSCORRUPTED;
1791 }
1792
1793 *ipp = ip;
1794 return 0;
1795 }
1796
1797 /******************************************************************************
1798 *
1799 * Log recover routines
1800 *
1801 ******************************************************************************
1802 */
1803 static const struct xlog_recover_item_ops *xlog_recover_item_ops[] = {
1804 &xlog_buf_item_ops,
1805 &xlog_inode_item_ops,
1806 &xlog_dquot_item_ops,
1807 &xlog_quotaoff_item_ops,
1808 &xlog_icreate_item_ops,
1809 &xlog_efi_item_ops,
1810 &xlog_efd_item_ops,
1811 &xlog_rui_item_ops,
1812 &xlog_rud_item_ops,
1813 &xlog_cui_item_ops,
1814 &xlog_cud_item_ops,
1815 &xlog_bui_item_ops,
1816 &xlog_bud_item_ops,
1817 &xlog_attri_item_ops,
1818 &xlog_attrd_item_ops,
1819 &xlog_xmi_item_ops,
1820 &xlog_xmd_item_ops,
1821 };
1822
1823 static const struct xlog_recover_item_ops *
1824 xlog_find_item_ops(
1825 struct xlog_recover_item *item)
1826 {
1827 unsigned int i;
1828
1829 for (i = 0; i < ARRAY_SIZE(xlog_recover_item_ops); i++)
1830 if (ITEM_TYPE(item) == xlog_recover_item_ops[i]->item_type)
1831 return xlog_recover_item_ops[i];
1832
1833 return NULL;
1834 }
1835
1836 /*
1837 * Sort the log items in the transaction.
1838 *
1839 * The ordering constraints are defined by the inode allocation and unlink
1840 * behaviour. The rules are:
1841 *
1842 * 1. Every item is only logged once in a given transaction. Hence it
1843 * represents the last logged state of the item. Hence ordering is
1844 * dependent on the order in which operations need to be performed so
1845 * required initial conditions are always met.
1846 *
1847 * 2. Cancelled buffers are recorded in pass 1 in a separate table and
1848 * there's nothing to replay from them so we can simply cull them
1849 * from the transaction. However, we can't do that until after we've
1850 * replayed all the other items because they may be dependent on the
1851 * cancelled buffer and replaying the cancelled buffer can remove it
1852 * form the cancelled buffer table. Hence they have tobe done last.
1853 *
1854 * 3. Inode allocation buffers must be replayed before inode items that
1855 * read the buffer and replay changes into it. For filesystems using the
1856 * ICREATE transactions, this means XFS_LI_ICREATE objects need to get
1857 * treated the same as inode allocation buffers as they create and
1858 * initialise the buffers directly.
1859 *
1860 * 4. Inode unlink buffers must be replayed after inode items are replayed.
1861 * This ensures that inodes are completely flushed to the inode buffer
1862 * in a "free" state before we remove the unlinked inode list pointer.
1863 *
1864 * Hence the ordering needs to be inode allocation buffers first, inode items
1865 * second, inode unlink buffers third and cancelled buffers last.
1866 *
1867 * But there's a problem with that - we can't tell an inode allocation buffer
1868 * apart from a regular buffer, so we can't separate them. We can, however,
1869 * tell an inode unlink buffer from the others, and so we can separate them out
1870 * from all the other buffers and move them to last.
1871 *
1872 * Hence, 4 lists, in order from head to tail:
1873 * - buffer_list for all buffers except cancelled/inode unlink buffers
1874 * - item_list for all non-buffer items
1875 * - inode_buffer_list for inode unlink buffers
1876 * - cancel_list for the cancelled buffers
1877 *
1878 * Note that we add objects to the tail of the lists so that first-to-last
1879 * ordering is preserved within the lists. Adding objects to the head of the
1880 * list means when we traverse from the head we walk them in last-to-first
1881 * order. For cancelled buffers and inode unlink buffers this doesn't matter,
1882 * but for all other items there may be specific ordering that we need to
1883 * preserve.
1884 */
1885 STATIC int
1886 xlog_recover_reorder_trans(
1887 struct xlog *log,
1888 struct xlog_recover *trans,
1889 int pass)
1890 {
1891 struct xlog_recover_item *item, *n;
1892 int error = 0;
1893 LIST_HEAD(sort_list);
1894 LIST_HEAD(cancel_list);
1895 LIST_HEAD(buffer_list);
1896 LIST_HEAD(inode_buffer_list);
1897 LIST_HEAD(item_list);
1898
1899 list_splice_init(&trans->r_itemq, &sort_list);
1900 list_for_each_entry_safe(item, n, &sort_list, ri_list) {
1901 enum xlog_recover_reorder fate = XLOG_REORDER_ITEM_LIST;
1902
1903 item->ri_ops = xlog_find_item_ops(item);
1904 if (!item->ri_ops) {
1905 xfs_warn(log->l_mp,
1906 "%s: unrecognized type of log operation (%d)",
1907 __func__, ITEM_TYPE(item));
1908 ASSERT(0);
1909 /*
1910 * return the remaining items back to the transaction
1911 * item list so they can be freed in caller.
1912 */
1913 if (!list_empty(&sort_list))
1914 list_splice_init(&sort_list, &trans->r_itemq);
1915 error = -EFSCORRUPTED;
1916 break;
1917 }
1918
1919 if (item->ri_ops->reorder)
1920 fate = item->ri_ops->reorder(item);
1921
1922 switch (fate) {
1923 case XLOG_REORDER_BUFFER_LIST:
1924 list_move_tail(&item->ri_list, &buffer_list);
1925 break;
1926 case XLOG_REORDER_CANCEL_LIST:
1927 trace_xfs_log_recover_item_reorder_head(log,
1928 trans, item, pass);
1929 list_move(&item->ri_list, &cancel_list);
1930 break;
1931 case XLOG_REORDER_INODE_BUFFER_LIST:
1932 list_move(&item->ri_list, &inode_buffer_list);
1933 break;
1934 case XLOG_REORDER_ITEM_LIST:
1935 trace_xfs_log_recover_item_reorder_tail(log,
1936 trans, item, pass);
1937 list_move_tail(&item->ri_list, &item_list);
1938 break;
1939 }
1940 }
1941
1942 ASSERT(list_empty(&sort_list));
1943 if (!list_empty(&buffer_list))
1944 list_splice(&buffer_list, &trans->r_itemq);
1945 if (!list_empty(&item_list))
1946 list_splice_tail(&item_list, &trans->r_itemq);
1947 if (!list_empty(&inode_buffer_list))
1948 list_splice_tail(&inode_buffer_list, &trans->r_itemq);
1949 if (!list_empty(&cancel_list))
1950 list_splice_tail(&cancel_list, &trans->r_itemq);
1951 return error;
1952 }
1953
1954 void
1955 xlog_buf_readahead(
1956 struct xlog *log,
1957 xfs_daddr_t blkno,
1958 uint len,
1959 const struct xfs_buf_ops *ops)
1960 {
1961 if (!xlog_is_buffer_cancelled(log, blkno, len))
1962 xfs_buf_readahead(log->l_mp->m_ddev_targp, blkno, len, ops);
1963 }
1964
1965 /*
1966 * Create a deferred work structure for resuming and tracking the progress of a
1967 * log intent item that was found during recovery.
1968 */
1969 void
1970 xlog_recover_intent_item(
1971 struct xlog *log,
1972 struct xfs_log_item *lip,
1973 xfs_lsn_t lsn,
1974 const struct xfs_defer_op_type *ops)
1975 {
1976 ASSERT(xlog_item_is_intent(lip));
1977
1978 xfs_defer_start_recovery(lip, &log->r_dfops, ops);
1979
1980 /*
1981 * Insert the intent into the AIL directly and drop one reference so
1982 * that finishing or canceling the work will drop the other.
1983 */
1984 xfs_trans_ail_insert(log->l_ailp, lip, lsn);
1985 lip->li_ops->iop_unpin(lip, 0);
1986 }
1987
1988 STATIC int
1989 xlog_recover_items_pass2(
1990 struct xlog *log,
1991 struct xlog_recover *trans,
1992 struct list_head *buffer_list,
1993 struct list_head *item_list)
1994 {
1995 struct xlog_recover_item *item;
1996 int error = 0;
1997
1998 list_for_each_entry(item, item_list, ri_list) {
1999 trace_xfs_log_recover_item_recover(log, trans, item,
2000 XLOG_RECOVER_PASS2);
2001
2002 if (item->ri_ops->commit_pass2)
2003 error = item->ri_ops->commit_pass2(log, buffer_list,
2004 item, trans->r_lsn);
2005 if (error)
2006 return error;
2007 }
2008
2009 return error;
2010 }
2011
2012 /*
2013 * Perform the transaction.
2014 *
2015 * If the transaction modifies a buffer or inode, do it now. Otherwise,
2016 * EFIs and EFDs get queued up by adding entries into the AIL for them.
2017 */
2018 STATIC int
2019 xlog_recover_commit_trans(
2020 struct xlog *log,
2021 struct xlog_recover *trans,
2022 int pass,
2023 struct list_head *buffer_list)
2024 {
2025 int error = 0;
2026 int items_queued = 0;
2027 struct xlog_recover_item *item;
2028 struct xlog_recover_item *next;
2029 LIST_HEAD (ra_list);
2030 LIST_HEAD (done_list);
2031
2032 #define XLOG_RECOVER_COMMIT_QUEUE_MAX 100
2033
2034 hlist_del_init(&trans->r_list);
2035
2036 error = xlog_recover_reorder_trans(log, trans, pass);
2037 if (error)
2038 return error;
2039
2040 list_for_each_entry_safe(item, next, &trans->r_itemq, ri_list) {
2041 trace_xfs_log_recover_item_recover(log, trans, item, pass);
2042
2043 switch (pass) {
2044 case XLOG_RECOVER_PASS1:
2045 if (item->ri_ops->commit_pass1)
2046 error = item->ri_ops->commit_pass1(log, item);
2047 break;
2048 case XLOG_RECOVER_PASS2:
2049 if (item->ri_ops->ra_pass2)
2050 item->ri_ops->ra_pass2(log, item);
2051 list_move_tail(&item->ri_list, &ra_list);
2052 items_queued++;
2053 if (items_queued >= XLOG_RECOVER_COMMIT_QUEUE_MAX) {
2054 error = xlog_recover_items_pass2(log, trans,
2055 buffer_list, &ra_list);
2056 list_splice_tail_init(&ra_list, &done_list);
2057 items_queued = 0;
2058 }
2059
2060 break;
2061 default:
2062 ASSERT(0);
2063 }
2064
2065 if (error)
2066 goto out;
2067 }
2068
2069 out:
2070 if (!list_empty(&ra_list)) {
2071 if (!error)
2072 error = xlog_recover_items_pass2(log, trans,
2073 buffer_list, &ra_list);
2074 list_splice_tail_init(&ra_list, &done_list);
2075 }
2076
2077 if (!list_empty(&done_list))
2078 list_splice_init(&done_list, &trans->r_itemq);
2079
2080 return error;
2081 }
2082
2083 STATIC void
2084 xlog_recover_add_item(
2085 struct list_head *head)
2086 {
2087 struct xlog_recover_item *item;
2088
2089 item = kzalloc(sizeof(struct xlog_recover_item),
2090 GFP_KERNEL | __GFP_NOFAIL);
2091 INIT_LIST_HEAD(&item->ri_list);
2092 list_add_tail(&item->ri_list, head);
2093 }
2094
2095 STATIC int
2096 xlog_recover_add_to_cont_trans(
2097 struct xlog *log,
2098 struct xlog_recover *trans,
2099 char *dp,
2100 int len)
2101 {
2102 struct xlog_recover_item *item;
2103 char *ptr, *old_ptr;
2104 int old_len;
2105
2106 /*
2107 * If the transaction is empty, the header was split across this and the
2108 * previous record. Copy the rest of the header.
2109 */
2110 if (list_empty(&trans->r_itemq)) {
2111 ASSERT(len <= sizeof(struct xfs_trans_header));
2112 if (len > sizeof(struct xfs_trans_header)) {
2113 xfs_warn(log->l_mp, "%s: bad header length", __func__);
2114 return -EFSCORRUPTED;
2115 }
2116
2117 xlog_recover_add_item(&trans->r_itemq);
2118 ptr = (char *)&trans->r_theader +
2119 sizeof(struct xfs_trans_header) - len;
2120 memcpy(ptr, dp, len);
2121 return 0;
2122 }
2123
2124 /* take the tail entry */
2125 item = list_entry(trans->r_itemq.prev, struct xlog_recover_item,
2126 ri_list);
2127
2128 old_ptr = item->ri_buf[item->ri_cnt-1].i_addr;
2129 old_len = item->ri_buf[item->ri_cnt-1].i_len;
2130
2131 ptr = kvrealloc(old_ptr, old_len, len + old_len, GFP_KERNEL);
2132 if (!ptr)
2133 return -ENOMEM;
2134 memcpy(&ptr[old_len], dp, len);
2135 item->ri_buf[item->ri_cnt-1].i_len += len;
2136 item->ri_buf[item->ri_cnt-1].i_addr = ptr;
2137 trace_xfs_log_recover_item_add_cont(log, trans, item, 0);
2138 return 0;
2139 }
2140
2141 /*
2142 * The next region to add is the start of a new region. It could be
2143 * a whole region or it could be the first part of a new region. Because
2144 * of this, the assumption here is that the type and size fields of all
2145 * format structures fit into the first 32 bits of the structure.
2146 *
2147 * This works because all regions must be 32 bit aligned. Therefore, we
2148 * either have both fields or we have neither field. In the case we have
2149 * neither field, the data part of the region is zero length. We only have
2150 * a log_op_header and can throw away the header since a new one will appear
2151 * later. If we have at least 4 bytes, then we can determine how many regions
2152 * will appear in the current log item.
2153 */
2154 STATIC int
2155 xlog_recover_add_to_trans(
2156 struct xlog *log,
2157 struct xlog_recover *trans,
2158 char *dp,
2159 int len)
2160 {
2161 struct xfs_inode_log_format *in_f; /* any will do */
2162 struct xlog_recover_item *item;
2163 char *ptr;
2164
2165 if (!len)
2166 return 0;
2167 if (list_empty(&trans->r_itemq)) {
2168 /* we need to catch log corruptions here */
2169 if (*(uint *)dp != XFS_TRANS_HEADER_MAGIC) {
2170 xfs_warn(log->l_mp, "%s: bad header magic number",
2171 __func__);
2172 ASSERT(0);
2173 return -EFSCORRUPTED;
2174 }
2175
2176 if (len > sizeof(struct xfs_trans_header)) {
2177 xfs_warn(log->l_mp, "%s: bad header length", __func__);
2178 ASSERT(0);
2179 return -EFSCORRUPTED;
2180 }
2181
2182 /*
2183 * The transaction header can be arbitrarily split across op
2184 * records. If we don't have the whole thing here, copy what we
2185 * do have and handle the rest in the next record.
2186 */
2187 if (len == sizeof(struct xfs_trans_header))
2188 xlog_recover_add_item(&trans->r_itemq);
2189 memcpy(&trans->r_theader, dp, len);
2190 return 0;
2191 }
2192
2193 ptr = xlog_kvmalloc(len);
2194 memcpy(ptr, dp, len);
2195 in_f = (struct xfs_inode_log_format *)ptr;
2196
2197 /* take the tail entry */
2198 item = list_entry(trans->r_itemq.prev, struct xlog_recover_item,
2199 ri_list);
2200 if (item->ri_total != 0 &&
2201 item->ri_total == item->ri_cnt) {
2202 /* tail item is in use, get a new one */
2203 xlog_recover_add_item(&trans->r_itemq);
2204 item = list_entry(trans->r_itemq.prev,
2205 struct xlog_recover_item, ri_list);
2206 }
2207
2208 if (item->ri_total == 0) { /* first region to be added */
2209 if (in_f->ilf_size == 0 ||
2210 in_f->ilf_size > XLOG_MAX_REGIONS_IN_ITEM) {
2211 xfs_warn(log->l_mp,
2212 "bad number of regions (%d) in inode log format",
2213 in_f->ilf_size);
2214 ASSERT(0);
2215 kvfree(ptr);
2216 return -EFSCORRUPTED;
2217 }
2218
2219 item->ri_total = in_f->ilf_size;
2220 item->ri_buf = kzalloc(item->ri_total * sizeof(xfs_log_iovec_t),
2221 GFP_KERNEL | __GFP_NOFAIL);
2222 }
2223
2224 if (item->ri_total <= item->ri_cnt) {
2225 xfs_warn(log->l_mp,
2226 "log item region count (%d) overflowed size (%d)",
2227 item->ri_cnt, item->ri_total);
2228 ASSERT(0);
2229 kvfree(ptr);
2230 return -EFSCORRUPTED;
2231 }
2232
2233 /* Description region is ri_buf[0] */
2234 item->ri_buf[item->ri_cnt].i_addr = ptr;
2235 item->ri_buf[item->ri_cnt].i_len = len;
2236 item->ri_cnt++;
2237 trace_xfs_log_recover_item_add(log, trans, item, 0);
2238 return 0;
2239 }
2240
2241 /*
2242 * Free up any resources allocated by the transaction
2243 *
2244 * Remember that EFIs, EFDs, and IUNLINKs are handled later.
2245 */
2246 STATIC void
2247 xlog_recover_free_trans(
2248 struct xlog_recover *trans)
2249 {
2250 struct xlog_recover_item *item, *n;
2251 int i;
2252
2253 hlist_del_init(&trans->r_list);
2254
2255 list_for_each_entry_safe(item, n, &trans->r_itemq, ri_list) {
2256 /* Free the regions in the item. */
2257 list_del(&item->ri_list);
2258 for (i = 0; i < item->ri_cnt; i++)
2259 kvfree(item->ri_buf[i].i_addr);
2260 /* Free the item itself */
2261 kfree(item->ri_buf);
2262 kfree(item);
2263 }
2264 /* Free the transaction recover structure */
2265 kfree(trans);
2266 }
2267
2268 /*
2269 * On error or completion, trans is freed.
2270 */
2271 STATIC int
2272 xlog_recovery_process_trans(
2273 struct xlog *log,
2274 struct xlog_recover *trans,
2275 char *dp,
2276 unsigned int len,
2277 unsigned int flags,
2278 int pass,
2279 struct list_head *buffer_list)
2280 {
2281 int error = 0;
2282 bool freeit = false;
2283
2284 /* mask off ophdr transaction container flags */
2285 flags &= ~XLOG_END_TRANS;
2286 if (flags & XLOG_WAS_CONT_TRANS)
2287 flags &= ~XLOG_CONTINUE_TRANS;
2288
2289 /*
2290 * Callees must not free the trans structure. We'll decide if we need to
2291 * free it or not based on the operation being done and it's result.
2292 */
2293 switch (flags) {
2294 /* expected flag values */
2295 case 0:
2296 case XLOG_CONTINUE_TRANS:
2297 error = xlog_recover_add_to_trans(log, trans, dp, len);
2298 break;
2299 case XLOG_WAS_CONT_TRANS:
2300 error = xlog_recover_add_to_cont_trans(log, trans, dp, len);
2301 break;
2302 case XLOG_COMMIT_TRANS:
2303 error = xlog_recover_commit_trans(log, trans, pass,
2304 buffer_list);
2305 /* success or fail, we are now done with this transaction. */
2306 freeit = true;
2307 break;
2308
2309 /* unexpected flag values */
2310 case XLOG_UNMOUNT_TRANS:
2311 /* just skip trans */
2312 xfs_warn(log->l_mp, "%s: Unmount LR", __func__);
2313 freeit = true;
2314 break;
2315 case XLOG_START_TRANS:
2316 default:
2317 xfs_warn(log->l_mp, "%s: bad flag 0x%x", __func__, flags);
2318 ASSERT(0);
2319 error = -EFSCORRUPTED;
2320 break;
2321 }
2322 if (error || freeit)
2323 xlog_recover_free_trans(trans);
2324 return error;
2325 }
2326
2327 /*
2328 * Lookup the transaction recovery structure associated with the ID in the
2329 * current ophdr. If the transaction doesn't exist and the start flag is set in
2330 * the ophdr, then allocate a new transaction for future ID matches to find.
2331 * Either way, return what we found during the lookup - an existing transaction
2332 * or nothing.
2333 */
2334 STATIC struct xlog_recover *
2335 xlog_recover_ophdr_to_trans(
2336 struct hlist_head rhash[],
2337 struct xlog_rec_header *rhead,
2338 struct xlog_op_header *ohead)
2339 {
2340 struct xlog_recover *trans;
2341 xlog_tid_t tid;
2342 struct hlist_head *rhp;
2343
2344 tid = be32_to_cpu(ohead->oh_tid);
2345 rhp = &rhash[XLOG_RHASH(tid)];
2346 hlist_for_each_entry(trans, rhp, r_list) {
2347 if (trans->r_log_tid == tid)
2348 return trans;
2349 }
2350
2351 /*
2352 * skip over non-start transaction headers - we could be
2353 * processing slack space before the next transaction starts
2354 */
2355 if (!(ohead->oh_flags & XLOG_START_TRANS))
2356 return NULL;
2357
2358 ASSERT(be32_to_cpu(ohead->oh_len) == 0);
2359
2360 /*
2361 * This is a new transaction so allocate a new recovery container to
2362 * hold the recovery ops that will follow.
2363 */
2364 trans = kzalloc(sizeof(struct xlog_recover), GFP_KERNEL | __GFP_NOFAIL);
2365 trans->r_log_tid = tid;
2366 trans->r_lsn = be64_to_cpu(rhead->h_lsn);
2367 INIT_LIST_HEAD(&trans->r_itemq);
2368 INIT_HLIST_NODE(&trans->r_list);
2369 hlist_add_head(&trans->r_list, rhp);
2370
2371 /*
2372 * Nothing more to do for this ophdr. Items to be added to this new
2373 * transaction will be in subsequent ophdr containers.
2374 */
2375 return NULL;
2376 }
2377
2378 STATIC int
2379 xlog_recover_process_ophdr(
2380 struct xlog *log,
2381 struct hlist_head rhash[],
2382 struct xlog_rec_header *rhead,
2383 struct xlog_op_header *ohead,
2384 char *dp,
2385 char *end,
2386 int pass,
2387 struct list_head *buffer_list)
2388 {
2389 struct xlog_recover *trans;
2390 unsigned int len;
2391 int error;
2392
2393 /* Do we understand who wrote this op? */
2394 if (ohead->oh_clientid != XFS_TRANSACTION &&
2395 ohead->oh_clientid != XFS_LOG) {
2396 xfs_warn(log->l_mp, "%s: bad clientid 0x%x",
2397 __func__, ohead->oh_clientid);
2398 ASSERT(0);
2399 return -EFSCORRUPTED;
2400 }
2401
2402 /*
2403 * Check the ophdr contains all the data it is supposed to contain.
2404 */
2405 len = be32_to_cpu(ohead->oh_len);
2406 if (dp + len > end) {
2407 xfs_warn(log->l_mp, "%s: bad length 0x%x", __func__, len);
2408 WARN_ON(1);
2409 return -EFSCORRUPTED;
2410 }
2411
2412 trans = xlog_recover_ophdr_to_trans(rhash, rhead, ohead);
2413 if (!trans) {
2414 /* nothing to do, so skip over this ophdr */
2415 return 0;
2416 }
2417
2418 /*
2419 * The recovered buffer queue is drained only once we know that all
2420 * recovery items for the current LSN have been processed. This is
2421 * required because:
2422 *
2423 * - Buffer write submission updates the metadata LSN of the buffer.
2424 * - Log recovery skips items with a metadata LSN >= the current LSN of
2425 * the recovery item.
2426 * - Separate recovery items against the same metadata buffer can share
2427 * a current LSN. I.e., consider that the LSN of a recovery item is
2428 * defined as the starting LSN of the first record in which its
2429 * transaction appears, that a record can hold multiple transactions,
2430 * and/or that a transaction can span multiple records.
2431 *
2432 * In other words, we are allowed to submit a buffer from log recovery
2433 * once per current LSN. Otherwise, we may incorrectly skip recovery
2434 * items and cause corruption.
2435 *
2436 * We don't know up front whether buffers are updated multiple times per
2437 * LSN. Therefore, track the current LSN of each commit log record as it
2438 * is processed and drain the queue when it changes. Use commit records
2439 * because they are ordered correctly by the logging code.
2440 */
2441 if (log->l_recovery_lsn != trans->r_lsn &&
2442 ohead->oh_flags & XLOG_COMMIT_TRANS) {
2443 error = xfs_buf_delwri_submit(buffer_list);
2444 if (error)
2445 return error;
2446 log->l_recovery_lsn = trans->r_lsn;
2447 }
2448
2449 return xlog_recovery_process_trans(log, trans, dp, len,
2450 ohead->oh_flags, pass, buffer_list);
2451 }
2452
2453 /*
2454 * There are two valid states of the r_state field. 0 indicates that the
2455 * transaction structure is in a normal state. We have either seen the
2456 * start of the transaction or the last operation we added was not a partial
2457 * operation. If the last operation we added to the transaction was a
2458 * partial operation, we need to mark r_state with XLOG_WAS_CONT_TRANS.
2459 *
2460 * NOTE: skip LRs with 0 data length.
2461 */
2462 STATIC int
2463 xlog_recover_process_data(
2464 struct xlog *log,
2465 struct hlist_head rhash[],
2466 struct xlog_rec_header *rhead,
2467 char *dp,
2468 int pass,
2469 struct list_head *buffer_list)
2470 {
2471 struct xlog_op_header *ohead;
2472 char *end;
2473 int num_logops;
2474 int error;
2475
2476 end = dp + be32_to_cpu(rhead->h_len);
2477 num_logops = be32_to_cpu(rhead->h_num_logops);
2478
2479 /* check the log format matches our own - else we can't recover */
2480 if (xlog_header_check_recover(log->l_mp, rhead))
2481 return -EIO;
2482
2483 trace_xfs_log_recover_record(log, rhead, pass);
2484 while ((dp < end) && num_logops) {
2485
2486 ohead = (struct xlog_op_header *)dp;
2487 dp += sizeof(*ohead);
2488 if (dp > end) {
2489 xfs_warn(log->l_mp, "%s: op header overrun", __func__);
2490 return -EFSCORRUPTED;
2491 }
2492
2493 /* errors will abort recovery */
2494 error = xlog_recover_process_ophdr(log, rhash, rhead, ohead,
2495 dp, end, pass, buffer_list);
2496 if (error)
2497 return error;
2498
2499 dp += be32_to_cpu(ohead->oh_len);
2500 num_logops--;
2501 }
2502 return 0;
2503 }
2504
2505 /* Take all the collected deferred ops and finish them in order. */
2506 static int
2507 xlog_finish_defer_ops(
2508 struct xfs_mount *mp,
2509 struct list_head *capture_list)
2510 {
2511 struct xfs_defer_capture *dfc, *next;
2512 struct xfs_trans *tp;
2513 int error = 0;
2514
2515 list_for_each_entry_safe(dfc, next, capture_list, dfc_list) {
2516 struct xfs_trans_res resv;
2517 struct xfs_defer_resources dres;
2518
2519 /*
2520 * Create a new transaction reservation from the captured
2521 * information. Set logcount to 1 to force the new transaction
2522 * to regrant every roll so that we can make forward progress
2523 * in recovery no matter how full the log might be.
2524 */
2525 resv.tr_logres = dfc->dfc_logres;
2526 resv.tr_logcount = 1;
2527 resv.tr_logflags = XFS_TRANS_PERM_LOG_RES;
2528
2529 error = xfs_trans_alloc(mp, &resv, dfc->dfc_blkres,
2530 dfc->dfc_rtxres, XFS_TRANS_RESERVE, &tp);
2531 if (error) {
2532 xlog_force_shutdown(mp->m_log, SHUTDOWN_LOG_IO_ERROR);
2533 return error;
2534 }
2535
2536 /*
2537 * Transfer to this new transaction all the dfops we captured
2538 * from recovering a single intent item.
2539 */
2540 list_del_init(&dfc->dfc_list);
2541 xfs_defer_ops_continue(dfc, tp, &dres);
2542 error = xfs_trans_commit(tp);
2543 xfs_defer_resources_rele(&dres);
2544 if (error)
2545 return error;
2546 }
2547
2548 ASSERT(list_empty(capture_list));
2549 return 0;
2550 }
2551
2552 /* Release all the captured defer ops and capture structures in this list. */
2553 static void
2554 xlog_abort_defer_ops(
2555 struct xfs_mount *mp,
2556 struct list_head *capture_list)
2557 {
2558 struct xfs_defer_capture *dfc;
2559 struct xfs_defer_capture *next;
2560
2561 list_for_each_entry_safe(dfc, next, capture_list, dfc_list) {
2562 list_del_init(&dfc->dfc_list);
2563 xfs_defer_ops_capture_abort(mp, dfc);
2564 }
2565 }
2566
2567 /*
2568 * When this is called, all of the log intent items which did not have
2569 * corresponding log done items should be in the AIL. What we do now is update
2570 * the data structures associated with each one.
2571 *
2572 * Since we process the log intent items in normal transactions, they will be
2573 * removed at some point after the commit. This prevents us from just walking
2574 * down the list processing each one. We'll use a flag in the intent item to
2575 * skip those that we've already processed and use the AIL iteration mechanism's
2576 * generation count to try to speed this up at least a bit.
2577 *
2578 * When we start, we know that the intents are the only things in the AIL. As we
2579 * process them, however, other items are added to the AIL. Hence we know we
2580 * have started recovery on all the pending intents when we find an non-intent
2581 * item in the AIL.
2582 */
2583 STATIC int
2584 xlog_recover_process_intents(
2585 struct xlog *log)
2586 {
2587 LIST_HEAD(capture_list);
2588 struct xfs_defer_pending *dfp, *n;
2589 int error = 0;
2590 #if defined(DEBUG) || defined(XFS_WARN)
2591 xfs_lsn_t last_lsn;
2592
2593 last_lsn = xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block);
2594 #endif
2595
2596 list_for_each_entry_safe(dfp, n, &log->r_dfops, dfp_list) {
2597 ASSERT(xlog_item_is_intent(dfp->dfp_intent));
2598
2599 /*
2600 * We should never see a redo item with a LSN higher than
2601 * the last transaction we found in the log at the start
2602 * of recovery.
2603 */
2604 ASSERT(XFS_LSN_CMP(last_lsn, dfp->dfp_intent->li_lsn) >= 0);
2605
2606 /*
2607 * NOTE: If your intent processing routine can create more
2608 * deferred ops, you /must/ attach them to the capture list in
2609 * the recover routine or else those subsequent intents will be
2610 * replayed in the wrong order!
2611 *
2612 * The recovery function can free the log item, so we must not
2613 * access dfp->dfp_intent after it returns. It must dispose of
2614 * @dfp if it returns 0.
2615 */
2616 error = xfs_defer_finish_recovery(log->l_mp, dfp,
2617 &capture_list);
2618 if (error)
2619 break;
2620 }
2621 if (error)
2622 goto err;
2623
2624 error = xlog_finish_defer_ops(log->l_mp, &capture_list);
2625 if (error)
2626 goto err;
2627
2628 return 0;
2629 err:
2630 xlog_abort_defer_ops(log->l_mp, &capture_list);
2631 return error;
2632 }
2633
2634 /*
2635 * A cancel occurs when the mount has failed and we're bailing out. Release all
2636 * pending log intent items that we haven't started recovery on so they don't
2637 * pin the AIL.
2638 */
2639 STATIC void
2640 xlog_recover_cancel_intents(
2641 struct xlog *log)
2642 {
2643 struct xfs_defer_pending *dfp, *n;
2644
2645 list_for_each_entry_safe(dfp, n, &log->r_dfops, dfp_list) {
2646 ASSERT(xlog_item_is_intent(dfp->dfp_intent));
2647
2648 xfs_defer_cancel_recovery(log->l_mp, dfp);
2649 }
2650 }
2651
2652 /*
2653 * Transfer ownership of the recovered pending work to the recovery transaction
2654 * and try to finish the work. If there is more work to be done, the dfp will
2655 * remain attached to the transaction. If not, the dfp is freed.
2656 */
2657 int
2658 xlog_recover_finish_intent(
2659 struct xfs_trans *tp,
2660 struct xfs_defer_pending *dfp)
2661 {
2662 int error;
2663
2664 list_move(&dfp->dfp_list, &tp->t_dfops);
2665 error = xfs_defer_finish_one(tp, dfp);
2666 if (error == -EAGAIN)
2667 return 0;
2668 return error;
2669 }
2670
2671 /*
2672 * This routine performs a transaction to null out a bad inode pointer
2673 * in an agi unlinked inode hash bucket.
2674 */
2675 STATIC void
2676 xlog_recover_clear_agi_bucket(
2677 struct xfs_perag *pag,
2678 int bucket)
2679 {
2680 struct xfs_mount *mp = pag->pag_mount;
2681 struct xfs_trans *tp;
2682 struct xfs_agi *agi;
2683 struct xfs_buf *agibp;
2684 int offset;
2685 int error;
2686
2687 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_clearagi, 0, 0, 0, &tp);
2688 if (error)
2689 goto out_error;
2690
2691 error = xfs_read_agi(pag, tp, 0, &agibp);
2692 if (error)
2693 goto out_abort;
2694
2695 agi = agibp->b_addr;
2696 agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
2697 offset = offsetof(xfs_agi_t, agi_unlinked) +
2698 (sizeof(xfs_agino_t) * bucket);
2699 xfs_trans_log_buf(tp, agibp, offset,
2700 (offset + sizeof(xfs_agino_t) - 1));
2701
2702 error = xfs_trans_commit(tp);
2703 if (error)
2704 goto out_error;
2705 return;
2706
2707 out_abort:
2708 xfs_trans_cancel(tp);
2709 out_error:
2710 xfs_warn(mp, "%s: failed to clear agi %d. Continuing.", __func__,
2711 pag->pag_agno);
2712 return;
2713 }
2714
2715 static int
2716 xlog_recover_iunlink_bucket(
2717 struct xfs_perag *pag,
2718 struct xfs_agi *agi,
2719 int bucket)
2720 {
2721 struct xfs_mount *mp = pag->pag_mount;
2722 struct xfs_inode *prev_ip = NULL;
2723 struct xfs_inode *ip;
2724 xfs_agino_t prev_agino, agino;
2725 int error = 0;
2726
2727 agino = be32_to_cpu(agi->agi_unlinked[bucket]);
2728 while (agino != NULLAGINO) {
2729 error = xfs_iget(mp, NULL,
2730 XFS_AGINO_TO_INO(mp, pag->pag_agno, agino),
2731 0, 0, &ip);
2732 if (error)
2733 break;
2734
2735 ASSERT(VFS_I(ip)->i_nlink == 0);
2736 ASSERT(VFS_I(ip)->i_mode != 0);
2737 xfs_iflags_clear(ip, XFS_IRECOVERY);
2738 agino = ip->i_next_unlinked;
2739
2740 if (prev_ip) {
2741 ip->i_prev_unlinked = prev_agino;
2742 xfs_irele(prev_ip);
2743
2744 /*
2745 * Ensure the inode is removed from the unlinked list
2746 * before we continue so that it won't race with
2747 * building the in-memory list here. This could be
2748 * serialised with the agibp lock, but that just
2749 * serialises via lockstepping and it's much simpler
2750 * just to flush the inodegc queue and wait for it to
2751 * complete.
2752 */
2753 error = xfs_inodegc_flush(mp);
2754 if (error)
2755 break;
2756 }
2757
2758 prev_agino = agino;
2759 prev_ip = ip;
2760 }
2761
2762 if (prev_ip) {
2763 int error2;
2764
2765 ip->i_prev_unlinked = prev_agino;
2766 xfs_irele(prev_ip);
2767
2768 error2 = xfs_inodegc_flush(mp);
2769 if (error2 && !error)
2770 return error2;
2771 }
2772 return error;
2773 }
2774
2775 /*
2776 * Recover AGI unlinked lists
2777 *
2778 * This is called during recovery to process any inodes which we unlinked but
2779 * not freed when the system crashed. These inodes will be on the lists in the
2780 * AGI blocks. What we do here is scan all the AGIs and fully truncate and free
2781 * any inodes found on the lists. Each inode is removed from the lists when it
2782 * has been fully truncated and is freed. The freeing of the inode and its
2783 * removal from the list must be atomic.
2784 *
2785 * If everything we touch in the agi processing loop is already in memory, this
2786 * loop can hold the cpu for a long time. It runs without lock contention,
2787 * memory allocation contention, the need wait for IO, etc, and so will run
2788 * until we either run out of inodes to process, run low on memory or we run out
2789 * of log space.
2790 *
2791 * This behaviour is bad for latency on single CPU and non-preemptible kernels,
2792 * and can prevent other filesystem work (such as CIL pushes) from running. This
2793 * can lead to deadlocks if the recovery process runs out of log reservation
2794 * space. Hence we need to yield the CPU when there is other kernel work
2795 * scheduled on this CPU to ensure other scheduled work can run without undue
2796 * latency.
2797 */
2798 static void
2799 xlog_recover_iunlink_ag(
2800 struct xfs_perag *pag)
2801 {
2802 struct xfs_agi *agi;
2803 struct xfs_buf *agibp;
2804 int bucket;
2805 int error;
2806
2807 error = xfs_read_agi(pag, NULL, 0, &agibp);
2808 if (error) {
2809 /*
2810 * AGI is b0rked. Don't process it.
2811 *
2812 * We should probably mark the filesystem as corrupt after we've
2813 * recovered all the ag's we can....
2814 */
2815 return;
2816 }
2817
2818 /*
2819 * Unlock the buffer so that it can be acquired in the normal course of
2820 * the transaction to truncate and free each inode. Because we are not
2821 * racing with anyone else here for the AGI buffer, we don't even need
2822 * to hold it locked to read the initial unlinked bucket entries out of
2823 * the buffer. We keep buffer reference though, so that it stays pinned
2824 * in memory while we need the buffer.
2825 */
2826 agi = agibp->b_addr;
2827 xfs_buf_unlock(agibp);
2828
2829 for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++) {
2830 error = xlog_recover_iunlink_bucket(pag, agi, bucket);
2831 if (error) {
2832 /*
2833 * Bucket is unrecoverable, so only a repair scan can
2834 * free the remaining unlinked inodes. Just empty the
2835 * bucket and remaining inodes on it unreferenced and
2836 * unfreeable.
2837 */
2838 xlog_recover_clear_agi_bucket(pag, bucket);
2839 }
2840 }
2841
2842 xfs_buf_rele(agibp);
2843 }
2844
2845 static void
2846 xlog_recover_process_iunlinks(
2847 struct xlog *log)
2848 {
2849 struct xfs_perag *pag;
2850 xfs_agnumber_t agno;
2851
2852 for_each_perag(log->l_mp, agno, pag)
2853 xlog_recover_iunlink_ag(pag);
2854 }
2855
2856 STATIC void
2857 xlog_unpack_data(
2858 struct xlog_rec_header *rhead,
2859 char *dp,
2860 struct xlog *log)
2861 {
2862 int i, j, k;
2863
2864 for (i = 0; i < BTOBB(be32_to_cpu(rhead->h_len)) &&
2865 i < (XLOG_HEADER_CYCLE_SIZE / BBSIZE); i++) {
2866 *(__be32 *)dp = *(__be32 *)&rhead->h_cycle_data[i];
2867 dp += BBSIZE;
2868 }
2869
2870 if (xfs_has_logv2(log->l_mp)) {
2871 xlog_in_core_2_t *xhdr = (xlog_in_core_2_t *)rhead;
2872 for ( ; i < BTOBB(be32_to_cpu(rhead->h_len)); i++) {
2873 j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
2874 k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
2875 *(__be32 *)dp = xhdr[j].hic_xheader.xh_cycle_data[k];
2876 dp += BBSIZE;
2877 }
2878 }
2879 }
2880
2881 /*
2882 * CRC check, unpack and process a log record.
2883 */
2884 STATIC int
2885 xlog_recover_process(
2886 struct xlog *log,
2887 struct hlist_head rhash[],
2888 struct xlog_rec_header *rhead,
2889 char *dp,
2890 int pass,
2891 struct list_head *buffer_list)
2892 {
2893 __le32 old_crc = rhead->h_crc;
2894 __le32 crc;
2895
2896 crc = xlog_cksum(log, rhead, dp, be32_to_cpu(rhead->h_len));
2897
2898 /*
2899 * Nothing else to do if this is a CRC verification pass. Just return
2900 * if this a record with a non-zero crc. Unfortunately, mkfs always
2901 * sets old_crc to 0 so we must consider this valid even on v5 supers.
2902 * Otherwise, return EFSBADCRC on failure so the callers up the stack
2903 * know precisely what failed.
2904 */
2905 if (pass == XLOG_RECOVER_CRCPASS) {
2906 if (old_crc && crc != old_crc)
2907 return -EFSBADCRC;
2908 return 0;
2909 }
2910
2911 /*
2912 * We're in the normal recovery path. Issue a warning if and only if the
2913 * CRC in the header is non-zero. This is an advisory warning and the
2914 * zero CRC check prevents warnings from being emitted when upgrading
2915 * the kernel from one that does not add CRCs by default.
2916 */
2917 if (crc != old_crc) {
2918 if (old_crc || xfs_has_crc(log->l_mp)) {
2919 xfs_alert(log->l_mp,
2920 "log record CRC mismatch: found 0x%x, expected 0x%x.",
2921 le32_to_cpu(old_crc),
2922 le32_to_cpu(crc));
2923 xfs_hex_dump(dp, 32);
2924 }
2925
2926 /*
2927 * If the filesystem is CRC enabled, this mismatch becomes a
2928 * fatal log corruption failure.
2929 */
2930 if (xfs_has_crc(log->l_mp)) {
2931 XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, log->l_mp);
2932 return -EFSCORRUPTED;
2933 }
2934 }
2935
2936 xlog_unpack_data(rhead, dp, log);
2937
2938 return xlog_recover_process_data(log, rhash, rhead, dp, pass,
2939 buffer_list);
2940 }
2941
2942 STATIC int
2943 xlog_valid_rec_header(
2944 struct xlog *log,
2945 struct xlog_rec_header *rhead,
2946 xfs_daddr_t blkno,
2947 int bufsize)
2948 {
2949 int hlen;
2950
2951 if (XFS_IS_CORRUPT(log->l_mp,
2952 rhead->h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM)))
2953 return -EFSCORRUPTED;
2954 if (XFS_IS_CORRUPT(log->l_mp,
2955 (!rhead->h_version ||
2956 (be32_to_cpu(rhead->h_version) &
2957 (~XLOG_VERSION_OKBITS))))) {
2958 xfs_warn(log->l_mp, "%s: unrecognised log version (%d).",
2959 __func__, be32_to_cpu(rhead->h_version));
2960 return -EFSCORRUPTED;
2961 }
2962
2963 /*
2964 * LR body must have data (or it wouldn't have been written)
2965 * and h_len must not be greater than LR buffer size.
2966 */
2967 hlen = be32_to_cpu(rhead->h_len);
2968 if (XFS_IS_CORRUPT(log->l_mp, hlen <= 0 || hlen > bufsize))
2969 return -EFSCORRUPTED;
2970
2971 if (XFS_IS_CORRUPT(log->l_mp,
2972 blkno > log->l_logBBsize || blkno > INT_MAX))
2973 return -EFSCORRUPTED;
2974 return 0;
2975 }
2976
2977 /*
2978 * Read the log from tail to head and process the log records found.
2979 * Handle the two cases where the tail and head are in the same cycle
2980 * and where the active portion of the log wraps around the end of
2981 * the physical log separately. The pass parameter is passed through
2982 * to the routines called to process the data and is not looked at
2983 * here.
2984 */
2985 STATIC int
2986 xlog_do_recovery_pass(
2987 struct xlog *log,
2988 xfs_daddr_t head_blk,
2989 xfs_daddr_t tail_blk,
2990 int pass,
2991 xfs_daddr_t *first_bad) /* out: first bad log rec */
2992 {
2993 xlog_rec_header_t *rhead;
2994 xfs_daddr_t blk_no, rblk_no;
2995 xfs_daddr_t rhead_blk;
2996 char *offset;
2997 char *hbp, *dbp;
2998 int error = 0, h_size, h_len;
2999 int error2 = 0;
3000 int bblks, split_bblks;
3001 int hblks = 1, split_hblks, wrapped_hblks;
3002 int i;
3003 struct hlist_head rhash[XLOG_RHASH_SIZE];
3004 LIST_HEAD (buffer_list);
3005
3006 ASSERT(head_blk != tail_blk);
3007 blk_no = rhead_blk = tail_blk;
3008
3009 for (i = 0; i < XLOG_RHASH_SIZE; i++)
3010 INIT_HLIST_HEAD(&rhash[i]);
3011
3012 hbp = xlog_alloc_buffer(log, hblks);
3013 if (!hbp)
3014 return -ENOMEM;
3015
3016 /*
3017 * Read the header of the tail block and get the iclog buffer size from
3018 * h_size. Use this to tell how many sectors make up the log header.
3019 */
3020 if (xfs_has_logv2(log->l_mp)) {
3021 /*
3022 * When using variable length iclogs, read first sector of
3023 * iclog header and extract the header size from it. Get a
3024 * new hbp that is the correct size.
3025 */
3026 error = xlog_bread(log, tail_blk, 1, hbp, &offset);
3027 if (error)
3028 goto bread_err1;
3029
3030 rhead = (xlog_rec_header_t *)offset;
3031
3032 /*
3033 * xfsprogs has a bug where record length is based on lsunit but
3034 * h_size (iclog size) is hardcoded to 32k. Now that we
3035 * unconditionally CRC verify the unmount record, this means the
3036 * log buffer can be too small for the record and cause an
3037 * overrun.
3038 *
3039 * Detect this condition here. Use lsunit for the buffer size as
3040 * long as this looks like the mkfs case. Otherwise, return an
3041 * error to avoid a buffer overrun.
3042 */
3043 h_size = be32_to_cpu(rhead->h_size);
3044 h_len = be32_to_cpu(rhead->h_len);
3045 if (h_len > h_size && h_len <= log->l_mp->m_logbsize &&
3046 rhead->h_num_logops == cpu_to_be32(1)) {
3047 xfs_warn(log->l_mp,
3048 "invalid iclog size (%d bytes), using lsunit (%d bytes)",
3049 h_size, log->l_mp->m_logbsize);
3050 h_size = log->l_mp->m_logbsize;
3051 }
3052
3053 error = xlog_valid_rec_header(log, rhead, tail_blk, h_size);
3054 if (error)
3055 goto bread_err1;
3056
3057 /*
3058 * This open codes xlog_logrec_hblks so that we can reuse the
3059 * fixed up h_size value calculated above. Without that we'd
3060 * still allocate the buffer based on the incorrect on-disk
3061 * size.
3062 */
3063 if (h_size > XLOG_HEADER_CYCLE_SIZE &&
3064 (rhead->h_version & cpu_to_be32(XLOG_VERSION_2))) {
3065 hblks = DIV_ROUND_UP(h_size, XLOG_HEADER_CYCLE_SIZE);
3066 if (hblks > 1) {
3067 kvfree(hbp);
3068 hbp = xlog_alloc_buffer(log, hblks);
3069 if (!hbp)
3070 return -ENOMEM;
3071 }
3072 }
3073 } else {
3074 ASSERT(log->l_sectBBsize == 1);
3075 h_size = XLOG_BIG_RECORD_BSIZE;
3076 }
3077
3078 dbp = xlog_alloc_buffer(log, BTOBB(h_size));
3079 if (!dbp) {
3080 kvfree(hbp);
3081 return -ENOMEM;
3082 }
3083
3084 memset(rhash, 0, sizeof(rhash));
3085 if (tail_blk > head_blk) {
3086 /*
3087 * Perform recovery around the end of the physical log.
3088 * When the head is not on the same cycle number as the tail,
3089 * we can't do a sequential recovery.
3090 */
3091 while (blk_no < log->l_logBBsize) {
3092 /*
3093 * Check for header wrapping around physical end-of-log
3094 */
3095 offset = hbp;
3096 split_hblks = 0;
3097 wrapped_hblks = 0;
3098 if (blk_no + hblks <= log->l_logBBsize) {
3099 /* Read header in one read */
3100 error = xlog_bread(log, blk_no, hblks, hbp,
3101 &offset);
3102 if (error)
3103 goto bread_err2;
3104 } else {
3105 /* This LR is split across physical log end */
3106 if (blk_no != log->l_logBBsize) {
3107 /* some data before physical log end */
3108 ASSERT(blk_no <= INT_MAX);
3109 split_hblks = log->l_logBBsize - (int)blk_no;
3110 ASSERT(split_hblks > 0);
3111 error = xlog_bread(log, blk_no,
3112 split_hblks, hbp,
3113 &offset);
3114 if (error)
3115 goto bread_err2;
3116 }
3117
3118 /*
3119 * Note: this black magic still works with
3120 * large sector sizes (non-512) only because:
3121 * - we increased the buffer size originally
3122 * by 1 sector giving us enough extra space
3123 * for the second read;
3124 * - the log start is guaranteed to be sector
3125 * aligned;
3126 * - we read the log end (LR header start)
3127 * _first_, then the log start (LR header end)
3128 * - order is important.
3129 */
3130 wrapped_hblks = hblks - split_hblks;
3131 error = xlog_bread_noalign(log, 0,
3132 wrapped_hblks,
3133 offset + BBTOB(split_hblks));
3134 if (error)
3135 goto bread_err2;
3136 }
3137 rhead = (xlog_rec_header_t *)offset;
3138 error = xlog_valid_rec_header(log, rhead,
3139 split_hblks ? blk_no : 0, h_size);
3140 if (error)
3141 goto bread_err2;
3142
3143 bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
3144 blk_no += hblks;
3145
3146 /*
3147 * Read the log record data in multiple reads if it
3148 * wraps around the end of the log. Note that if the
3149 * header already wrapped, blk_no could point past the
3150 * end of the log. The record data is contiguous in
3151 * that case.
3152 */
3153 if (blk_no + bblks <= log->l_logBBsize ||
3154 blk_no >= log->l_logBBsize) {
3155 rblk_no = xlog_wrap_logbno(log, blk_no);
3156 error = xlog_bread(log, rblk_no, bblks, dbp,
3157 &offset);
3158 if (error)
3159 goto bread_err2;
3160 } else {
3161 /* This log record is split across the
3162 * physical end of log */
3163 offset = dbp;
3164 split_bblks = 0;
3165 if (blk_no != log->l_logBBsize) {
3166 /* some data is before the physical
3167 * end of log */
3168 ASSERT(!wrapped_hblks);
3169 ASSERT(blk_no <= INT_MAX);
3170 split_bblks =
3171 log->l_logBBsize - (int)blk_no;
3172 ASSERT(split_bblks > 0);
3173 error = xlog_bread(log, blk_no,
3174 split_bblks, dbp,
3175 &offset);
3176 if (error)
3177 goto bread_err2;
3178 }
3179
3180 /*
3181 * Note: this black magic still works with
3182 * large sector sizes (non-512) only because:
3183 * - we increased the buffer size originally
3184 * by 1 sector giving us enough extra space
3185 * for the second read;
3186 * - the log start is guaranteed to be sector
3187 * aligned;
3188 * - we read the log end (LR header start)
3189 * _first_, then the log start (LR header end)
3190 * - order is important.
3191 */
3192 error = xlog_bread_noalign(log, 0,
3193 bblks - split_bblks,
3194 offset + BBTOB(split_bblks));
3195 if (error)
3196 goto bread_err2;
3197 }
3198
3199 error = xlog_recover_process(log, rhash, rhead, offset,
3200 pass, &buffer_list);
3201 if (error)
3202 goto bread_err2;
3203
3204 blk_no += bblks;
3205 rhead_blk = blk_no;
3206 }
3207
3208 ASSERT(blk_no >= log->l_logBBsize);
3209 blk_no -= log->l_logBBsize;
3210 rhead_blk = blk_no;
3211 }
3212
3213 /* read first part of physical log */
3214 while (blk_no < head_blk) {
3215 error = xlog_bread(log, blk_no, hblks, hbp, &offset);
3216 if (error)
3217 goto bread_err2;
3218
3219 rhead = (xlog_rec_header_t *)offset;
3220 error = xlog_valid_rec_header(log, rhead, blk_no, h_size);
3221 if (error)
3222 goto bread_err2;
3223
3224 /* blocks in data section */
3225 bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
3226 error = xlog_bread(log, blk_no+hblks, bblks, dbp,
3227 &offset);
3228 if (error)
3229 goto bread_err2;
3230
3231 error = xlog_recover_process(log, rhash, rhead, offset, pass,
3232 &buffer_list);
3233 if (error)
3234 goto bread_err2;
3235
3236 blk_no += bblks + hblks;
3237 rhead_blk = blk_no;
3238 }
3239
3240 bread_err2:
3241 kvfree(dbp);
3242 bread_err1:
3243 kvfree(hbp);
3244
3245 /*
3246 * Submit buffers that have been dirtied by the last record recovered.
3247 */
3248 if (!list_empty(&buffer_list)) {
3249 if (error) {
3250 /*
3251 * If there has been an item recovery error then we
3252 * cannot allow partial checkpoint writeback to
3253 * occur. We might have multiple checkpoints with the
3254 * same start LSN in this buffer list, and partial
3255 * writeback of a checkpoint in this situation can
3256 * prevent future recovery of all the changes in the
3257 * checkpoints at this start LSN.
3258 *
3259 * Note: Shutting down the filesystem will result in the
3260 * delwri submission marking all the buffers stale,
3261 * completing them and cleaning up _XBF_LOGRECOVERY
3262 * state without doing any IO.
3263 */
3264 xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
3265 }
3266 error2 = xfs_buf_delwri_submit(&buffer_list);
3267 }
3268
3269 if (error && first_bad)
3270 *first_bad = rhead_blk;
3271
3272 /*
3273 * Transactions are freed at commit time but transactions without commit
3274 * records on disk are never committed. Free any that may be left in the
3275 * hash table.
3276 */
3277 for (i = 0; i < XLOG_RHASH_SIZE; i++) {
3278 struct hlist_node *tmp;
3279 struct xlog_recover *trans;
3280
3281 hlist_for_each_entry_safe(trans, tmp, &rhash[i], r_list)
3282 xlog_recover_free_trans(trans);
3283 }
3284
3285 return error ? error : error2;
3286 }
3287
3288 /*
3289 * Do the recovery of the log. We actually do this in two phases.
3290 * The two passes are necessary in order to implement the function
3291 * of cancelling a record written into the log. The first pass
3292 * determines those things which have been cancelled, and the
3293 * second pass replays log items normally except for those which
3294 * have been cancelled. The handling of the replay and cancellations
3295 * takes place in the log item type specific routines.
3296 *
3297 * The table of items which have cancel records in the log is allocated
3298 * and freed at this level, since only here do we know when all of
3299 * the log recovery has been completed.
3300 */
3301 STATIC int
3302 xlog_do_log_recovery(
3303 struct xlog *log,
3304 xfs_daddr_t head_blk,
3305 xfs_daddr_t tail_blk)
3306 {
3307 int error;
3308
3309 ASSERT(head_blk != tail_blk);
3310
3311 /*
3312 * First do a pass to find all of the cancelled buf log items.
3313 * Store them in the buf_cancel_table for use in the second pass.
3314 */
3315 error = xlog_alloc_buf_cancel_table(log);
3316 if (error)
3317 return error;
3318
3319 error = xlog_do_recovery_pass(log, head_blk, tail_blk,
3320 XLOG_RECOVER_PASS1, NULL);
3321 if (error != 0)
3322 goto out_cancel;
3323
3324 /*
3325 * Then do a second pass to actually recover the items in the log.
3326 * When it is complete free the table of buf cancel items.
3327 */
3328 error = xlog_do_recovery_pass(log, head_blk, tail_blk,
3329 XLOG_RECOVER_PASS2, NULL);
3330 if (!error)
3331 xlog_check_buf_cancel_table(log);
3332 out_cancel:
3333 xlog_free_buf_cancel_table(log);
3334 return error;
3335 }
3336
3337 /*
3338 * Do the actual recovery
3339 */
3340 STATIC int
3341 xlog_do_recover(
3342 struct xlog *log,
3343 xfs_daddr_t head_blk,
3344 xfs_daddr_t tail_blk)
3345 {
3346 struct xfs_mount *mp = log->l_mp;
3347 struct xfs_buf *bp = mp->m_sb_bp;
3348 struct xfs_sb *sbp = &mp->m_sb;
3349 int error;
3350
3351 trace_xfs_log_recover(log, head_blk, tail_blk);
3352
3353 /*
3354 * First replay the images in the log.
3355 */
3356 error = xlog_do_log_recovery(log, head_blk, tail_blk);
3357 if (error)
3358 return error;
3359
3360 if (xlog_is_shutdown(log))
3361 return -EIO;
3362
3363 /*
3364 * We now update the tail_lsn since much of the recovery has completed
3365 * and there may be space available to use. If there were no extent or
3366 * iunlinks, we can free up the entire log. This was set in
3367 * xlog_find_tail to be the lsn of the last known good LR on disk. If
3368 * there are extent frees or iunlinks they will have some entries in the
3369 * AIL; so we look at the AIL to determine how to set the tail_lsn.
3370 */
3371 xfs_ail_assign_tail_lsn(log->l_ailp);
3372
3373 /*
3374 * Now that we've finished replaying all buffer and inode updates,
3375 * re-read the superblock and reverify it.
3376 */
3377 xfs_buf_lock(bp);
3378 xfs_buf_hold(bp);
3379 error = _xfs_buf_read(bp, XBF_READ);
3380 if (error) {
3381 if (!xlog_is_shutdown(log)) {
3382 xfs_buf_ioerror_alert(bp, __this_address);
3383 ASSERT(0);
3384 }
3385 xfs_buf_relse(bp);
3386 return error;
3387 }
3388
3389 /* Convert superblock from on-disk format */
3390 xfs_sb_from_disk(sbp, bp->b_addr);
3391 xfs_buf_relse(bp);
3392
3393 /* re-initialise in-core superblock and geometry structures */
3394 mp->m_features |= xfs_sb_version_to_features(sbp);
3395 xfs_reinit_percpu_counters(mp);
3396 error = xfs_initialize_perag(mp, sbp->sb_agcount, sbp->sb_dblocks,
3397 &mp->m_maxagi);
3398 if (error) {
3399 xfs_warn(mp, "Failed post-recovery per-ag init: %d", error);
3400 return error;
3401 }
3402 mp->m_alloc_set_aside = xfs_alloc_set_aside(mp);
3403
3404 /* Normal transactions can now occur */
3405 clear_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate);
3406 return 0;
3407 }
3408
3409 /*
3410 * Perform recovery and re-initialize some log variables in xlog_find_tail.
3411 *
3412 * Return error or zero.
3413 */
3414 int
3415 xlog_recover(
3416 struct xlog *log)
3417 {
3418 xfs_daddr_t head_blk, tail_blk;
3419 int error;
3420
3421 /* find the tail of the log */
3422 error = xlog_find_tail(log, &head_blk, &tail_blk);
3423 if (error)
3424 return error;
3425
3426 /*
3427 * The superblock was read before the log was available and thus the LSN
3428 * could not be verified. Check the superblock LSN against the current
3429 * LSN now that it's known.
3430 */
3431 if (xfs_has_crc(log->l_mp) &&
3432 !xfs_log_check_lsn(log->l_mp, log->l_mp->m_sb.sb_lsn))
3433 return -EINVAL;
3434
3435 if (tail_blk != head_blk) {
3436 /* There used to be a comment here:
3437 *
3438 * disallow recovery on read-only mounts. note -- mount
3439 * checks for ENOSPC and turns it into an intelligent
3440 * error message.
3441 * ...but this is no longer true. Now, unless you specify
3442 * NORECOVERY (in which case this function would never be
3443 * called), we just go ahead and recover. We do this all
3444 * under the vfs layer, so we can get away with it unless
3445 * the device itself is read-only, in which case we fail.
3446 */
3447 if ((error = xfs_dev_is_read_only(log->l_mp, "recovery"))) {
3448 return error;
3449 }
3450
3451 /*
3452 * Version 5 superblock log feature mask validation. We know the
3453 * log is dirty so check if there are any unknown log features
3454 * in what we need to recover. If there are unknown features
3455 * (e.g. unsupported transactions, then simply reject the
3456 * attempt at recovery before touching anything.
3457 */
3458 if (xfs_sb_is_v5(&log->l_mp->m_sb) &&
3459 xfs_sb_has_incompat_log_feature(&log->l_mp->m_sb,
3460 XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN)) {
3461 xfs_warn(log->l_mp,
3462 "Superblock has unknown incompatible log features (0x%x) enabled.",
3463 (log->l_mp->m_sb.sb_features_log_incompat &
3464 XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN));
3465 xfs_warn(log->l_mp,
3466 "The log can not be fully and/or safely recovered by this kernel.");
3467 xfs_warn(log->l_mp,
3468 "Please recover the log on a kernel that supports the unknown features.");
3469 return -EINVAL;
3470 }
3471
3472 /*
3473 * Delay log recovery if the debug hook is set. This is debug
3474 * instrumentation to coordinate simulation of I/O failures with
3475 * log recovery.
3476 */
3477 if (xfs_globals.log_recovery_delay) {
3478 xfs_notice(log->l_mp,
3479 "Delaying log recovery for %d seconds.",
3480 xfs_globals.log_recovery_delay);
3481 msleep(xfs_globals.log_recovery_delay * 1000);
3482 }
3483
3484 xfs_notice(log->l_mp, "Starting recovery (logdev: %s)",
3485 log->l_mp->m_logname ? log->l_mp->m_logname
3486 : "internal");
3487
3488 error = xlog_do_recover(log, head_blk, tail_blk);
3489 set_bit(XLOG_RECOVERY_NEEDED, &log->l_opstate);
3490 }
3491 return error;
3492 }
3493
3494 /*
3495 * In the first part of recovery we replay inodes and buffers and build up the
3496 * list of intents which need to be processed. Here we process the intents and
3497 * clean up the on disk unlinked inode lists. This is separated from the first
3498 * part of recovery so that the root and real-time bitmap inodes can be read in
3499 * from disk in between the two stages. This is necessary so that we can free
3500 * space in the real-time portion of the file system.
3501 *
3502 * We run this whole process under GFP_NOFS allocation context. We do a
3503 * combination of non-transactional and transactional work, yet we really don't
3504 * want to recurse into the filesystem from direct reclaim during any of this
3505 * processing. This allows all the recovery code run here not to care about the
3506 * memory allocation context it is running in.
3507 */
3508 int
3509 xlog_recover_finish(
3510 struct xlog *log)
3511 {
3512 unsigned int nofs_flags = memalloc_nofs_save();
3513 int error;
3514
3515 error = xlog_recover_process_intents(log);
3516 if (error) {
3517 /*
3518 * Cancel all the unprocessed intent items now so that we don't
3519 * leave them pinned in the AIL. This can cause the AIL to
3520 * livelock on the pinned item if anyone tries to push the AIL
3521 * (inode reclaim does this) before we get around to
3522 * xfs_log_mount_cancel.
3523 */
3524 xlog_recover_cancel_intents(log);
3525 xfs_alert(log->l_mp, "Failed to recover intents");
3526 xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
3527 goto out_error;
3528 }
3529
3530 /*
3531 * Sync the log to get all the intents out of the AIL. This isn't
3532 * absolutely necessary, but it helps in case the unlink transactions
3533 * would have problems pushing the intents out of the way.
3534 */
3535 xfs_log_force(log->l_mp, XFS_LOG_SYNC);
3536
3537 xlog_recover_process_iunlinks(log);
3538
3539 /*
3540 * Recover any CoW staging blocks that are still referenced by the
3541 * ondisk refcount metadata. During mount there cannot be any live
3542 * staging extents as we have not permitted any user modifications.
3543 * Therefore, it is safe to free them all right now, even on a
3544 * read-only mount.
3545 */
3546 error = xfs_reflink_recover_cow(log->l_mp);
3547 if (error) {
3548 xfs_alert(log->l_mp,
3549 "Failed to recover leftover CoW staging extents, err %d.",
3550 error);
3551 /*
3552 * If we get an error here, make sure the log is shut down
3553 * but return zero so that any log items committed since the
3554 * end of intents processing can be pushed through the CIL
3555 * and AIL.
3556 */
3557 xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
3558 error = 0;
3559 goto out_error;
3560 }
3561
3562 out_error:
3563 memalloc_nofs_restore(nofs_flags);
3564 return error;
3565 }
3566
3567 void
3568 xlog_recover_cancel(
3569 struct xlog *log)
3570 {
3571 if (xlog_recovery_needed(log))
3572 xlog_recover_cancel_intents(log);
3573 }
3574
3575
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